Problem with a custom task form

I use Exchange 2003 and Outlook 2003. I have created a custom Work Order
task form in Outlook and published it in the Public folder. The form allows
various people to approve steps (user fields) in the Work Order task . This
procedure works fine for everyone in the company except for 2 people. When
they get to a certain step, they seem to revert back to a previous step
(user field state) in the process. The first person who received this
problem has a new computer built from scratch. She has now moved to another
position in the company. Her replacement is now getting the same problem.

- Their profiles are the same as others who work fine.

- We have cleared the forms cache.

- She has logged on to another machine and tried it. It works OK initially
and then she will start getting the problem on another machine.