Use only Admin login. User login gives problems as you noticed.
Why? Because both PR and EN need all the resources it can get and users don't have sufficient resources.
Not only do you need to run PPro/Encore with an Administrative permission account, in some instances you also need to take an additional step... at least for CS5
Run as Administrator http://forums.adobe.com/thread/969395
Things may be changing, though:
Not sure Adobe Anywhere will change this one. If anything, I can see Adobe Anywhere absolutely requiring an Admin account to work through network security.
Our lab has just had CS6 installed on it, running Win 7 enterprise. A user account will open a Premiere Pro project. I've done it. That was only to check that everything worked ok. I edited a couple of clips and stuck them on a sequence (16:9 PAL DV) and it played them ok and the project was saved back to the USB hard drive OK.
I have also opened up encore, made a new project and saved it to the USB HDD. No assets were added to it, just checking that the preference files had copied from the central server to the machine, so that users have certain options already pre-selected.
What exactly are the problems with Win 7 enterprise?