DierctX multiplayer issua

CFP Ver;
OS: Vista Business x64 (DX10)
I’ve experienced a fatal problem with multiplayer connection.
If I try to connect direct/play with a local application as Host (IVAP - that communicate with internet) and another local applicationas as Client, (Flight Simulator 9.1) the connection fail, I mean the multiplayer doesn’t start.
This happens also if both firewall and defence+ are deactivated, and also if CFP is not launched.
The problem desapperars only if I uninstall CFP.
This doesn’t happens with same version of CFP and XP Pro SP2
Reguards, and many tnx for this very good firewall. Wave

P.S. I’ve posted in other section and a forum member suggested me to post here, sorry for double post