Whenever I start Liberkey I get this message "Cannot run Check software updates (silent)". Also selecting Tools/Software update gives the same message. How do I fix the checking for new software versions?

I think (you or) your antivirus deleted the Liberkey Version Checker application located into LiberkeyTools folder
Download the Liberkey Platform version and replace folder LiberkeyTools\LbkAppVCheck (something like that)

In addition, check your antivirus and put LiberkeyTools folder into the application whitelist.