Cannot see other's availabilty

Dist.
there is an user in our office that nobody can see her avaialbility before
sending meetings inivitation... it only shows as tentative even if she is
busy.
She can see other's availability but we cannot see hers
There is a mix bw office 2003 and 2007 in our company.

Also, I noticed that she setup outlook to deliver all to her pst file
instead of mailbox. I didnt try to move this yet cause I tried several
options and I want to go to her desk with a final solution otherwise looks
like we are kicking the ball till hits the goal

Any thoughts?
I do appreciate

Thanks,
Mau