HELP: Windows/UNIX client - server

Good day all..

I have developed a client/server application for both UNIX and windows.
The server for windows successfully obtains data sent from the unix client.
But..the unix SERVER does not recieve the data from the windows client.
UX Client to UX server: Data OK
Win Client to Win Server: Data OK

The UNIX server responds to the windows client connection successfully,
Therefore the socket connection is successful, but when reading
the data used by send in the win client, the data length/pointer
is invalid.

I would appreciate it if anyone could enlighten me as to why this
problem is occurring..

Thanks
  James