Mixed reviews from Soviet bloc. Most applaud Gorbachev's diplomatic triumph, but internal problems dampen enthusiasm

Mikhail Gorbachev's Eastern European allies applauded the disarmament agreement he signed in Washington. The cheers greeting Mr. Gorbachev in East Berlin Friday were, to a large extent, genuine. Analysts say a relaxation of superpower tensions permits East Europeans to develop their own relations with the West.

But behind the applause, analysts perceive undercurrents of anxiety. The summit comes just when East Europeans are introducing glasnost (openness) and perestroika (restructuring) in their own societies.

In the past, a combination of Soviet reform and East-West thaw led to political convulsions: in Hungary in 1956, in Czechoslovakia in 1968, and in Poland in 1980. If the superpowers reduce tensions too quickly, analysts say the region's balance once again could be upset.

``The East Europeans have so many worries themselves at this time, the referendum in Poland, the imposition of income taxes in Hungary, the recent demonstrations in Romania,'' says Pierre Hassner, an East-West specialist at Paris's Center for International Studies. ``A new era of d'etente could unleash unknown forces.''

The absence of Romanian leader Nicolae Ceausescu's in East Berlin symbolized those fears. Mr. Ceausescu opposes Gorbachev's reforms and likes to display his independence from the Soviet leader. Also, his own internal problems are mounting. Just last month, workers rioted against low wages and harsh living conditions.

``Somewhat like the French on the other side, Ceaucescu didn't like the fact that the summit went over his head and ignored his own disarmament proposals,'' says Vladimir Kusin, chief analyst at the US-sponsored Radio Free Europe in Munich. ``He may be facing a power struggle within the Romanian establishment.''

Hard-line Czechoslovakia is also having difficulty adapting itself to Gorbachev's diplomacy. The Prague government's legitimacy resides in the Soviet troops which brought it to power after the 1968 invasion. Foreign Minister Bohuslav Chnoupek recently admitted that some elements of the establishment worry about a rapid disarmament process which would lead to the withdrawal of Soviet forces.

Not all East Europeans see the same difficulties. Hungary has constructed an ``open'' relationship with Austria and just obtained a crucial $500 million loan from West Germany. East Germany has even more economic reasons to maintain ties with West Germany.

Polish leader Wojciech Jaruzelski has staked his political future on good relations with both Gorbachev and the West. He has even put forward his own disarmament proposals for Central Europe.

General Jaruzelski's constituents seem more skeptical. A recent visit to Poland by this correspondent showed both officials and the public preoccupied with domestic problems. The arms agreement won't bring more meat into the stores, many people noted.

Some opposition figures recognize that d'etente gives them space to push for reform. Other people hope to see practical benefits from the West - more films, books, and rock and dance groups.

But some East Europeans, such as Czech writer Vaclav Havel, insist on talking about human rights before talking about arms. Until communist regimes are at peace with themselves, says Mr. Havel, they will be unstable and represent a danger to their neighbors.