Really bugging me - parallels deactivating itself

OK, I had this problem and I re-installed Parallels 4.0 only a day or two ago, I was hoping the issue was resolved but apparently not.
After being installed I checked, it had already been registered to my account, and it said the product was activated and showed my activation key I used.
I clicked Parallels 4.0 in my Dock to open it, instead of opening with my list of VMs (as it does when it's registered) it does nothing, if I right click it and select Virtual Machine List it's either greyed out or it opens the installer for installing a new OS into it.

If I go help -> Activate Product it says it's not activated, if I input my serial again, it says it is invalid and to click a link.
Does anyone know how to fix this?

Kind Regards

 

Identical problem Beta 5

I have just had the same problem with beta 5. I had new key from parallels for the beta when I first installed it. Now I can't do anything! Key is just ignored and Parallels will not activate.