There is a bug in the PSP version of Puzzle Quest: Challenge of the Warlords which was brought up on the Infinity Forums. This bug apparently involves the special abilities of your companions in the game. In a nutshell, their abilities do not work. This bug was confirmed by Steve Fawkner, a developer for Infinite Interactive.

Mr. Fawkner's reaction was rather positive stating that "it doesn't break the storyline at all" and even said that "it really shouldn't affect the gameplay in any significant way".  Then he presented an explanation on why it was difficult to spot:

The difficulty in spotting this bug was more about timing than anything else. I do owe anybody affected an explanation... this is not intended as an excuse... merely an example of how easily these things can happen. With 1-2 days to go until Gold Master, a change was made to the code that caused this problem (it had been working bug free for 8-9 months up until then).

He added that they just forgot about it as they were more preoccupied fixing bigger problems with the game. The playtesters at Sony must have missed it as well because they had no idea that it was supposed to be there.

As for a fix, certain people have been asking for a patch that can be installed on a memory stick to fix this. It has even been suggested that they should have a trade-in scheme to allow those who want a patched UMD to trade in their old one. So far no confirmed fixes have been announced, more on this as we get more information.

Special thanks to Haoyong for the tip!