Behaviour Protection freezes Windows 7 SP1 when accessing network executables

Whenever I try to access an executeable on a SMB-Network-Server (\server\share\any.exe) with the Avast behaviour proection, my PC (Windows 7 SP1) freezes completely after about 15 seconds of inactivity.
When I disable behaviour protection, it works fine.
I would love to send in a more detailed system report but I did not find any such buttons in Avast (e.g. for reporting a bug with system log).

This happened with Avast 5 as well as Avast 6 (6.0.1000). If I remember correctly the problem started to show up after I installed SP1.

I did some more research:
My netbook has the same problem when connecting to that server. Exactly the same behaviour, turning off behaviour protection (I hope that is the correct translation) will fix it.

However when I run the exact same file from a different machine (netbook loads it from PC, not server), it works fine. It must have something to do with the server.

All machines are Windows 7 SP1.

Another update:
I updated Avast on the server to 6.0.1000, installed a new NForce Network driver from Windowsupdate and rebooted.
The affected server has a Point of View ION330 board with network drivers from 2009, now updated to 73.3.5.0).
After the reboot, it seems to work correctly again.