Dolores: If it has been a long time since you last used it then unzipping this into
C:\Program Files\BearShare\db might help: http://www3.telus.net/Aaron_Walkhouse/connect.zip
BearShare has to be shut down when you do it.

Christoph: The heartbeat server probably crashed. It doesn't matter.
Since you have b25, go to Setup/Service and do this:

Leave it in ultrapeer mode for a while and your performance will improve.
Once you start some downloads, if the speeds seem to be sluggish, reverse those settings.