Endpoint Protection

I recently installed SEPM MR4 on a windows Server 2008(standard) machine, i had it download updates then successfully pushed to the server itself. Since then i have not been able to successfully push to any of the systems on the network again. The computers on the network is more of windows vista, 2 other 2008 servers and 1 2003 server.  If i start pushing via migration and deployment, it starts going but it takes a very long while moving, then it fails and write error 2.

Is there any special configuration or setting i have to do on the SEPM server or on the ISA server on the network. Do i  need to open any port on the ISA machine

Please check this document

Symantec Endpoint Protection: Preparing computers that run Windows Vista for remote client deployment

http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2007091021513648

since you have two machines, you can export your package, save it , run it on the client machine locally that would also work.

You can keep the created installation package at a centralized location and the clients can download it and run the setup.exe file. Once the installation is done the clients would start communicating with the SEPM. One thing for sure if the installation goes through successfully and if the clients are not able to communicate then you can check for communication between this client and the SEPM server machine.

http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2009082701244448

You should have SEP version 11.0.5002 (MR5) when using Windows Server 2008