I have all my movies on my hard drive.  Is there a way to add them to DVD Profiler all at once?

Short answer: No.

Longer answer: You could use a barcode scanner to add your DVDs to DVD Profiler if you still have the cases with the UPCs on the covers. Or, you could create a text file with a list of the UPCs of all of your DVDs and use the UPC Import plugin to import your titles into DVD Profiler. The downfall of doing it this way though is that after importing your DVDs you would have to edit each title individually afterwards to personalize them if you wish to add the actual purchase info such as date of purchase, location purchased and price paid.