First, what OS did you install SEPM on?
What version of IIS are you using?
You said, Remote Workplace, I am not familiar with it, but I assume it has ports that need opening and you probably installed the Firewall component on the server, when you installed the client (not recommended). So you locked yourself out of the machine (remotely).
Can you get to a terminal on the Server itself (physical) where you can access the machine?
Next thing to know, what other services, if any, are you running on this box? WSUS, Web Sites, etc.
If you can get to a terminal, and you can open up the SEPM manager, than we can look at diagnosing the problem.
Thanks.