It sounds like it might be a startup script. If this is the case the script is running as SYSTEM. You have a couple of options...
1. Create a hybrid startup and login script. Startup for admin things, and logon for user related things. 2. There is RunAsInteractiveUser. This is a UDF that has been pretty thoroughly tested by the kixtart community.
There is another way that involves a registry hack, but I'm not going to advise you go that direction.
