The problems with running from Windows XP Limited accounts are actual well known and some years old. I just stumbled upon them now just because I wanted to stop using Administrator mode, as per instructions.
The problem is that Windows XP has heaps of permissions, behind the scenes, which have come along after Windows, being one person really, was begun.
I have decided to give up on running under Limited accounts and use other approaches from inside Admin account.
a) use something like a program which drops rights/permissions from the running program, just as it is started