Difficulty joining my WPA2 network

Only occasionally can my known network be joined, needing to remove and re-enter password, it also gets dumped for no apparent reason. Have Apple Airport Extreme router.
Driving me insane.

Any ideas?

I *think* I have a similar problem... I keep having to re-enter the WPA2 password for it to even pick up a network even though it is stored in there...
It used to work fine but then I had to get a new hard drive installed and ended up with Leopard (I had whatever was before that...) and now it doesn't work.

I've found that if you fully turn off wifi or log out and then back in again, it'll work again. Hopefully, 10.5.5 fixed it- seems stable so far to me.