[Samba] The semaphore timeout period has expired

[Hamish]

Hello everyone
I have samba 3.0.3pre2-SuSE running on SuSE 9.0 i386, this is from SuSE 
rpms not source. The box is joined to a 2k3 domain, wbinfo works fine, 
acls work and users are authenticated properly.
I had a problem yesterday and cannot seem to find a solution:

I have been copying data across from the old SBS server, this seems to 
work fine for about 5 minutes, then completely crashes the samba box (i 
cannot ssh into it, even sitting at the terminal there is no response).
The windows box (old server) that was copying the files displays the 
error "The semaphore timeout period has expired" and no shares can be 
accessed.

The files being copied during crash were different sizes (i thought it 
might be because of huge files) : 1st crash the file was 380Mb, second 
crash 74k.
I checked log.smbd and there do not seem to be any error messages (just 
connect and close messages).

Is it possible that this is not actually a samba problem? (possibly a 
network driver problem - it is an Asustek 3c940 1000Base? - using module 
sk98lin)

Thanks,