Cannot logon to new user account

I'm having two problems and I think they are related to each other:

Problem #1: I'm running Windows XP Pro. I can create a new user's account
OK (with adminsitrator privilege), but when I tried to logon to it, the
process starts and I receive a message telling me my personal settings are
being implemented, then I receive a message saying 'logging off' and I'm
returned to
the logon screen.

Problem #2: When I try to install a program, the installation process starts
and then I receive the message "Failed to install ISKernel Files. Make sure
you have appropriate privileges on this machine."

Any help anyone can provide me would be appreciated.