postgresql failed to establish a connection to <pg server name>

Dear all,

i really have a serious problem with the connection to postgres windows 2008R2 x64 Server,
am using Npgsql .net using VB.NET and trying to make a stress test about the connections ammount, trying to open about 200 sessions from a client Windows7 PC.
Randomly I get an error message in my vb.net from the npgsql saying that "postgresql failed to establish a connection to < pg server name >" that happen for about 10 percent of the connections randomly, meanwhile on the server itself I found errors like:

EOF on Client-Connection
No connection could be made because the target machine actively refused it.

When I try to run my program from postgres server locally then all goes fine with no error at all, only from a remote PC or Server, I HAVE STOPED ALL WINDOWS FIREWAL and ANY FIREWAL SOFTWARE on both Server and client, but still facing the problem.

Please Help

Adel

________________________________
A. Klinkhammer F?rderanlagen Kreative Lager- und Produktionslogistik GmbH
Sitz der Gesellschaft: N?rnberg * Registergericht: Amtsgericht N?rnberg, HRB 15958
Gesch?ftsf?hrer: Frank Klinkhammer, Gerald Schulz
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