This one is really weird. I had a perfectly working Eclipse + Android 2.2 SDK working in both Administrator account and LUA (Limited User Account) unde
Try running eclipse by downloading the binary and unzipping and directly running the .exe rather than "installing" it. The android tools should work this way if you configure the appropriate paths to them, and if eclipse isn't "installed" but simply run from a the archive folder, it should try to download plugins and such into its own directory (owned by your user), which may solve your problem.
I doubt the Android developers who built the tools run under LUAs, so they probably didn't run into this problem...