Sorry, 3rd party. Last time I saw it, it came bundled with Norton System Works 2003. This link may be of help:
http://www.softwaredirections.com/ptree/
Though I can't remember if that is it for sure or not. Like I said, I haven't used it in 4 years. There is a 3rd party tool out there somewhere called "depends." and you can use it to check what files a .exe or .dll file requires to run. I saw it at a client I work for, but have no clue of it's origin. That is kind of useless information I guess, but maybe you can hunt it down. :-/
i686-linux 75 Posting Whiz in Training