Outlook Permissions

[Dave]

I have several Windows NT 4.0 workstations which are
running Office 2000. These machines have had registry and
permission changes done bo other third party agencies.
Whenever and Admin person logs in to them, Outlook can be
configured and everything works fine.When a regular user
log in, I get this message when configuring their
mail "The Microsoft Exchange Server cannot be contacted.
Please check your network settings. I believe this is a
registry/permission setting since it works fine when
logged in as an admin.
I just need to know what to check/change to make this work
correctly.

Thanks!
Dave