Lots of tips can be found in the SGA forum for MOH.
http://www.pbbans.com/forums/medal-of-honor-f556.html
But I shall outline a few things to check.
1. Make sure PB is up to date update it using your GSP control panel or ask your GSP to do this for you.
2. Ensure you enter the RCON port in the webtool and the join port in the AccCP when you set up streaming.
3. If the webtool doesn't work try manually editing the pbsv.cfg I use the one from the MCi
http://www.pbbans.com/mci-view-moh-pbsv-37.html