Is it about checking security of your system ?

Judging by his post I'd assume it's for checking system's he's authorized to perform audits on.

May be we can suggest something alternative, knowing more about your application.

Most of the major password cracking programs out there just aren't that good. They don't allow for the flexibility to customize your rules. Anyone who's half decent at cracking won't just sit down and brute force it, they'll look for the weakest link, find out everything they can and construct a profile of the user, then make very targeted guesses at their password. You'd be amazed how effective this can be.