Make sure the lock ID set in the software is the same as the lock ID set within the lock itself. You can edit the lock ID on the lock from menu #1 under Lock ID in the Lock Setup menu. In the software just click edit on the lock itself to edit the lock ID number. If they do not match it will not function.
Ensure you are using the latest version of the PCMU software. We will have the complete set of the latest editions of the software on our technical support page in the very near future. Meanwhile we can provide the software to you directly upon request. You can upgrade to the latest version (not a free upgrade) here: http://rums.advancedactuators.com/update/publish.htm
(it has a 30 day free trial, make sure you backup your old data using the maintain menu before the upgrade).