Corel PSP X2

[TEL]

Hi,
My pc is with Vista Home Premium, I'm the only user on this pc ie. not logging in, being administrator. However, I think already here I'm having a problem. I have turned off the UAC, but still get the question about permission/or ok to run several programs. I thought that that UAC would always give me permision after the first time running the programs as admin. But not, so there I turned off the UAC, but it doesn't seem to work.
So, am I the admin user or what? If not, how do I log on as admin when there no such account?? Under c:users theres: applic data, common and me.
Well, you've probably understand by now that I'm very confused with the UAC, admin and security rules in Vista...

Anyway, I don't know if the above is the background for my main problem:

I'm trying to install Corels PSP X2, but get different error message depending on if trying to install it under the suggested pc-path on the c-drive (crogram files\...) or if I try to install under the "Common"-part of the system.

When trying to install under crogram files\... I get the error message: "Error 1920.Service ProtexisLicensing (ProtexisLicensing) failed to start. Verify that you have sufficient priviliges to start system services." ...*read, read, read...* Aha, the forum told me how to turn off the ProtexisLicensing. Tryed to install again, that worked almost ok, but now I get the same error message as when I tried to install the program under the common part of pc. And the error message is: "No valid temp directory defined. Please define a valid temp directory in windows. Application will now exit." Where is the valid temp directory supposed to be? And how do I change this without reinstalling the program again?

I miss my PSP on the pc! Any help is highly appreciated!
And I do apologize if I've placed this question in the wrong part of the forum.