Clarence Boudreau says he knew his $6 million investment in Cuba was in trouble when President Fidel Castro, who had backed the deal and even loaned him a helicopter to survey a site, stood him up for dinner.

``They had all my drawings, all my engineering data, so they didn't need me anymore,'' the Canadian businessman said. ``I tell you, if you're going to do business in Cuba these days, the No. 1 rule is cash on the table.''

Boudreau is not alone in his vexation with Havana. More and more, foreign investors are complaining that it has become increasingly difficult for them to work and profit in Cuba over the past year.

Government officials are cracking down on technically illegal but long-tolerated deals, sending tax auditors after foreigners, cutting out middlemen and muscling their way into businesses, say U.S., Canadian and European analysts who monitor Cuba's investment climate.

State-controlled firms are increasingly backing out on deals, delaying payments on their debts and pressuring foreign business people to buy locally made but low-quality products, the analysts added.

Just how many foreigners have been affected is not known because most refuse to make their problems public, fearing retaliation by a Communist government that controls the courts, police and their visas.

Investor complains

``People only start telling the truth about Cuba when they get screwed,'' said Arnold Guettler, 58, a German-Canadian investor who claims Cuba stole $1 million worth of machinery he shipped to Havana.

Cuban Embassy officials in Ottawa declined to comment on the Boudreau and Guettler cases, but Canadian Foreign Ministry spokesman Christian Girouard said the government considered them ordinary business disagreements.

``What we have, in effect, are commercial disputes. While these two ventures have run into difficulties, other Canadian companies have enjoyed considerable success in Cuba,'' Girouard said.

The Western experts on Cuba blame the recent spate of problems on a Havana campaign to tighten controls on foreign investments. The controls were only grudgingly eased when Soviet subsidies ended in 1991 and sparked a crisis.

Some of the foreign investors who rushed in at the time were too small or inexperienced to carry out the ambitious, even risky deals they were proposing to Cuban officials who also lacked experience, the experts added.

``It's not like in the early years, when we paid much attention to what foreigners wanted to do here. Now we go out to look for partners for a project we want,'' Foreign Investment Minister Ibrahim Ferradaz said last month.

Self-promotion

Cuba still portrays itself as a good investment opportunity, boasting of 365 joint ventures between foreign firms and the Cuban government, and more than $2 billion in direct foreign investments. About 600 foreign firms have opened offices in Havana, according to official reports.

But the recent spate of complaints has clouded Cuba's investment image.

``The bloom is off,'' said a U.S. analyst who monitors business opportunities on the island. ``There's definitely a lack of enthusiasm among foreign companies in Cuba today.''

Said Boudreau: ``They think they don't need foreign investors anymore, so they cheat. They think there's light at the end of their [economic] tunnel, so they steal.''

Complaint publicized

Boudreau was one of the first to go public with his complaint, rising at a meeting between Ferradaz and Canadian business people in Toronto in March to tell his tale of woe and demand redress.

Boudreau complained that his Ontario firm, FirstKey Project Technologies, spent $6 million over 18 months putting together the engineering and financial details on a $350 million power plant construction project in central Cuba.

Castro attended the signing of the preliminary agreements with Cuban government firms, loaned him a helicopter to inspect a site and even allowed his staff to stay at government guest houses in Havana, Boudreau said.

But everything changed on the night Boudreau was supposed to dine with Castro and sign the final documents. Castro stood him up and sent an aide to tell him the government no longer needed the plant, he said.

His outburst at the Ferradaz meeting was followed by another from an insurance company executive who grumbled that Havana was forcing the firm to channel all payments to clients in Cuba through government agencies, according to Peter Foster, a Canadian journalist who attended the meeting.

Another businessman quietly approached him after the meeting with another complaint, Boudreau said.

Boudreau said the man claimed to have sold imported supplies to foreign-run hotels in Cuba for years, but said a government official ordered him to stop in January because only the government could engage in domestic trade.

When he protested, he was thrown in jail briefly, lost his Mercedes-Benz and was hassled at the Havana airport as he flew back to Canada, the man told Boudreau. Contacted by The Herald, the man declined comment.

`All kinds of people'

Canadians are not the only victims.

``There are Mexicans complaining, Caribbeans complaining, French, Italians, all kinds of people,'' said a U.S. analyst who monitors foreign investments in Cuba.

Roberto Ferrari, Swiss-Argentine manager of the Spanish-administered Havana Libre Hotel, was ordered to leave in March because he ``complained too publicly about the government and the bureaucracy,'' a friend said.

A Spaniard who had a computer firm in Havana claimed he was forced out by a top government official who started a rival business. A Mexican agent in Havana for a European firm said the government forced his parent firm to cut him out of a deal to avoid paying him a commission.

Cuban firms have been so late paying debts that many foreign companies recently started requiring letters of credit for the full amount of exports to the island, not just part as is usual.

``The Cubans were always a bit late but always paid, always robbing Peter to pay Paul. But now it's so bad that people are in effect asking for full payment up front,'' said a Spanish businessman in Havana.

Most common among the foreign investors' complaints are cases like Guettler's, where seemingly solid deals with government ministries or state-owned firms collapse suddenly and almost inexplicably.

``I had seven contracts with Cuban enterprises and suddenly someone came along and said those agencies were not authorized to do business with foreigners,'' said Guettler, whose Neo-Form company went into Cuba in 1996 to sell his patented process for lightweight concrete extrusions.

He rented a warehouse in Havana and shipped in more than $1 million worth of machinery and a Chevy Blazer last summer. And then his troubles started, Guettler said.

Authorities have blocked him from entering the warehouse and have seized his vehicle. Guettler said he believes the machinery is now being operated by a new government-foreign venture, without his permission.

``I want to accuse them of theft and industrial spying,'' said Guettler, whose contracts with Cuba require any dispute be mediated by courts in Spain. ``I am a very stubborn person. They are not going to steal anything from me.''

Satisfaction unlikely

Experts on foreign investments in Cuba predict Boudreau and Guettler are unlikely to get satisfaction from Havana.

``Doing business with the Cubans is complicated,'' said a European lawyer who advises several clients doing business on the island. ``They don't have a long history of dealing with foreign investors. They don't have very clear laws. Sometimes they don't even understand the complexities of the deals they sign.''

``And if you complain in public,'' he added, ``the game is over.''