disable UDP Checksum Offload

I develop some woftware under Windows Vista and DotNet 2.0. It sends UDP
packets to an XP macjine across the LAN.
When code runs in Vista I get with in the sniffer running in the XP machine
a checksum error and some hint that I may need to disable UDP Checksum
Offload(Another XP which also sends packets causes, no problem)
Can anyone advice how to do that?
Regards
James

Hi all,I figured out in the LAN card configuration that I can disable the

Hi all,
I figured out in the LAN card configuration that I can disable the checksum.
However, doing so did not change the situation at all. I still get the
checksum error indication in the sniffer, but worth is that the application
continue to fail when networking is between Windows Vista and Windows XP.
When both peers are in Vista - verything is OK. Also, when both peers run in
XP machines, no errors.
Regards
Games

machine

Is the sniffer Ethereal/Wireshark? If so, what version?

Is the sniffer Ethereal/Wireshark?  If so, what version?