By NICHOLAS KULISH

VIENNA - Herbert Stepic, an Austrian banker, and Laszlo Seres, a Hungarian entrepreneur, have never met, but they are tied together by 20 years of business, tens of millions of dollars of debt and the dream of borderless prosperity made possible by a united Europe.

Now they are struggling to nurse their businesses through the economic downturn. Europe, which appeared so tightly bound during the boom years, has left them to find solutions to the financial crisis on their own.

The drive toward European unity required big doses of both political and financial capital, with Western European banks showering cash on Eastern European entrepreneurs like Mr. Seres, who used the money to build hundreds of square meters of office space for a booming Budapest, Hungary’s capital.

Mr. Seres is just one of Mr. Stepic’s 15 million customers at the huge bank Raiffeisen International, served by some 3,200 branches across Eastern Europe.

This eastward expansion seemed for years an inexorable and predictable process, with membership in the European Union followed by entry into the euro currency zone.

But as money from the West fueled a debtladen binge in the East, that grand vision may have blinded investors to the risks of cross-border, cross-currency lending. As the financial crisis struck, Mr. Stepic’s bank, like many in Austria, found its loan portfolio deteriorating alarmingly. Meanwhile, Mr. Seres was forced into a mad scramble for cash to try to save his real estate empire. He pulled $400,000 from his own savings to keep his latest development from going bust.

“For more than a month I hardly slept,” Mr. Seres said of the period at the height of the financial crisis when he feared he might not be able to make his payments on time.

Today, the aggressive lending for ambitious new projects has given way to a slow, painful unwinding. From Stockholm and Milan to Riga, Latvia and Sofia, businessmen on the front lines of integration had hoped that the European Union’s executive body in Brussels and the region’s central bank would put together a bold financial rescue and stimulus package to stabilize banks and cushion the severe slump in the East, especially in Hungary.

The World Bank’s president, Robert B. Zoellick, joined Austrian officials in calling for more assistance from Brussels to stabilize the region.

Instead, the leaders of the wealthier nations of Western Europe, who had welcomed their Eastern neighbors into institutions like NATO and the European Union, looked inward as the crisis worsened, rushing to protect their own companies and banks but resisting most pleas to save jobs or shore up banks elsewhere.

“We are not fighting against bad will. They are simply unable and not prepared to change the normal pattern,” Mr. Stepic, the banker, said of European leaders earlier this summer. “The main thing is that we don’t make geopolitical mistakes, that something that we all have been fighting for, for 50 years, to create a united Europe, is now forgotten suddenly.”

The countries that use the euro chose instead to go into what Adam S. Posen, the deputy director of the Peterson Institute for International Economics in Washington, called a “defensive crouch” to protect the euro, which some worried would weaken if governments piled up debt to bail out troubled banks or other companies. Mr. Posen called that a short-sighted approach that ignored the financial bonds between Europe’s constituent regions. “Failure to respond to the financial crisis in Eastern Europe is itself the greatest threat to the future growth and stability of the euro area,” Mr. Posen said.

Mr. Stepic said that 20 years ago he first began pushing for his bank, Raiffeisen Zentralbank, to capitalize on the crumbling of communism. The cold war years had relegated Austria to relative backwater status. But Raiffeisen could now expand by founding new banks in Poland, Slovakia, the Czech Republic, Bulgaria and Croatia as well as Hungary.

The time was “a unique chance for Austria, a unique chance for Europe, a unique chance for our own organization,” said Mr. Stepic, deputy chairman at Raiffeisen Zentralbank, Raiffeisen International’s parent company.

That opportunity was presented to businessmen like Mr. Seres. In 1998 he borrowed about $2 million from Raiffeisen to finance new office building projects. “I’m a very conservative businessman,” he said. “But you know if you get into a big real estate dealing you cannot do it without a bank.”

Such ties proliferated around the region, as Europe became reconnected. Swedish banks made significant investments in the Baltics. French, Italian and Belgian banks moved into the former Warsaw Pact. Austrian banks were in the forefront.

In 2004, the European Union celebrated the entry of 10 new members, including Hungary and seven other former Communist states of Eastern Europe, followed in 2007 by Romania and Bulgaria.

But the former Eastern Bloc, so reliant on financing from abroad, suddenly began to look shaky last year. The cash that had streamed into Eastern Europe was abruptly pulled out.

“Suddenly the banks stopped lending money,” Mr. Seres said.

In countries like France and Germany, talk of severe devaluations in Eastern European currencies has led to protectionist policies. The European Central Bank, at the same time, is refusing to relax the stringent criteria for joining the monetary union.

Mr. Stepic’s bank, Raiffeisen International, has seen the value of loans more than 90 days overdue nearly triple to almost $5.2 billion at the end of the second quarter in June compared with nearly $2 billion a year earlier.

Mr. Seres shored up his own capital position by selling 30 percent of one real estate venture. “Nobody knows what is the value on the market, because no transactions are on the market,” he said. “Nobody buys buildings now. We call it ‘sit out’ in Hungary. You sit and wait. Wait and see.”