Resolved Security certificate fails

I am running XP-Pro SP3.

I wanted to install the Blackberry Playbook Desktop manager, but as soon as the file starts the install, I get the message "Installation files cannot be verified. Please verify the Installation Package and try again ".

I've tried to say to accept but it will not.

Blackberry phone support is stumped, she said nobody has heard of this before.

We went into the certificate of the problem file (a .CAB) but when I change the permission, it does not actually change.

Any ideas???

(I will be away from my PC till Wed. 11 Apr, when BB said she will call me to try something else.)

 

Consider this thread solved and closed.

After an hour with a different BB tech (phone support) who knew what he was doing, and after trying several fixes that didn't work, he finally determined the problem.

My Win XP was missing a critical update relating to boot sector certificates handling.
30 sec after installing the update the app installed without incident.