Can't Sign In, IS Reports Already Signed In

Interprise Suite Version: 2007 SP5.1

Problem:

When signing in as a user into IS, IS reports already signed in (even though this user is "not" already signed in).

Solution:

Run SQL statement to set IsSignIn field = 0 in table SystemUserAccount for specific user.  e.g. update SystemUserAccount set IsSignIn = 0 where UserCode = 'admin'