Wow, that's a long living bug... I have it too: TightVNC 1.03 client on windows, Vine Server 3.0 (1016). Screen freezes, mouse works, request-refresh fixes it for a while (~2-10 minutes).

Seems to happen when I'm actively doing lots of keyboard and mouse things, but that's might be me noticing it.

OSX 10.5.5, Intel.

Also probably happen with Ultra VNC 1.0.5 viever. (switched to TightVNC before I knew request-refresh "fixes" it).