Party poker wait list problem

[ineedmoneybad]

Sometimes when I have multi tables open I join the list, then get the prompt window saying my seat is available. When I click take the seat the table opens but I cannot sit down, the open seat has a reserved sign on it. I wait awhile and keep getting the seat avaible prompt but unable to sit. Anyone else have this problem and know how to fix it? Recently got a new computer and still having the same problem.
Thanks