I had to re-install my Vista Operating System and while re-installing my softwares, I spent almost one hour trying to install BlackBerry Desktop Manager 6.1 on my PC. An ICT nightmare i must say, later found out that the issue was an invalid certificate, a missing CA, and the instructions on RIM’s site doesnt seem to resolve the issue.
So your error like mine was
The installation files cannot be validated. Please verify the installer package and try again
The reason is that the .cab and .msi setup files are signed with a certificate which cannot be validated…
On RIMs KnowledgeBase
The installer package is signed using a certificate trust that the target computer cannot verify or does not trust.
The installation is being performed in a limited-rights environment.
My Eventual Fix
Right Click and Download this Blackberry Manager Certificate to your Computer
Open Internet Explorer and go to Internet Options. Switch to the Content Tab as shown in the image below and then click on Certificates.
On that page, click on import to launch a Menu that will guide you through the importation of the BlackBerry Manager Certificate you just downloaded above.
Once the import has been successfully completed, simply close Internet Explorer and try your BlackBerry Software installation again.
You should be able to install free now