compiling models for steam

I've started playing around with prop models from 3ds Max to Source (thanks Generalvivi for the tuts).

When I goto compile my model using StudioMDL or Wunderboy's GUI I get the following error message:

SteamStartup() failed: SteamStartup(0xf,0x0012F188) failed with error 1: Failed to duplicate pipe handle, Win32 Error 6 "The handle is invalid."

I've even tried compiling qc's provided with the SDK and I still get this message.

After attempting a compile, I get the same message if I run any game or SDK app from Steam and I have to re-install/repair Steam.

Searched the net and checked the official Steam forums but haven't found a solution. btw I'm using Vista so that may have something to do with it.

Quote from Wunderboy

Got steam started?

Yep, after doing some further reading I found the error message was a generic Vista error (Win32 Error 6). Completely disabling UAC resolved it and my models compile fine now.