I had a chance to take a quick look at it, it does use a "screen scraper" type approach to getting the data from ezboard. This does have quite a few downfalls and would I suspect be unlikely to work 100%, for instance only members that have posted can be imported, passwords need to be reassigned to all members etc etc.
Personally I think you'd be better off starting your new forum off clean and just leaving the old ezboard there for people who wish to see older posts. Of course I don't know what sort of content your ezboard forums conatin so I may be way off base there.
I'm gong to try running it on a forum shortly to see how well it actually works importing to phpbb