I'm using kde 4.4 (rc3) and since yesterday, i can't connecte to gtalk.

Kopete connect, disconnect, connect, disconnect, ...

I have the same problem. Gtalk keeps connecting and disconnecting if I login with Kopete on two different machines. If I run Pidgin on both machines, or Pidgin on one machine and Kopete on the other, everything is fine. Does anyone else have this problem?

Unusual. Please file a bug report at bugs.kde.org

I found a reason of such behavior. By default Resource is the same - 'Kopete'. If the name of the Resource is different on two machines, then the problem disappears.

That is a problem with Kopete not using machine specific data as part of the name, which is a bug.