Piriform Defraggler hanging at 100% of Analysis on XP

We recently tried running Defraggler on my wife's computer, which is running XP. It works on the main disc but when we run Analysis on the extra hard drive she has installed, t doesn't show the health tab,and it goes to 100%and doesn't complete ever. The drive is working and all other programs show it as normal. But Defraggler hangs, shows no health,and won't defrag it.

Please help! What's going on?