Can't access locked files from thumb drive using different computer

I installed VPL to a thumb drive and encrypted my files to that same thumb drive, thinking I could then access the program and files to any computer I happen to be using (running the program and files from the thumb drive). But, alas, when I tried this on a different computer, after attaching the thumb drive and trying to run the VPL executable, it doesn't ask me for my password but rather thinks my program is not registered. My only option is to run in demo mode. I did that, but of course, in demo mode my previously saved encrypted files can't be unlocked.
What;'s the deal?

Did you purchase a 2nd code to use VPL on your 2nd pc? If not, you would need to do so - as each code only allows you one active install.