Network connection lost while writing files - reading works

[wumpus]

Hello together,
i´ve got a Problem with my Amahi/Fedora 14 Server.

If I copy large files eg Videos from my PC to my mediaserver, i get the "Windows" message, that the "connection is lost". ....after n-times "retry" the file is copied.
There no problems while reading large files, maybe >8TB
I have no problems to write large files to my (Linux based Fritzbox) NAS.

..and I have no Ideas about the network Messages.
br Rainer