WHen you change user accounts, are you leaving FileMaker launched on the first user account? I believe this should work if you first quit filemaker before changing user accounts.
PhilModJunk, sorry about that but you've misunderstood my problem.
This error happens ONLY if I open Filemaker Pro and connect to Filemaker Server using Account A in my computer.
If I login and use Account B in my computer it will work, If I use Filemaker Pro and connect to the server using another computer it will work.