Dismounted....
Same as above in the OP since the chdir() within cats.php didnt do anything except cause an error.
Here is the gist of what I did...
1. Wrote cats.php a standalone php file, that you can call directly from your browser. Check it out:
www.gamegavel.com/forums/cats.php. It generates a nice list of categories from my Auction site.
2. Then I went to the plugins manager, and just did a simple include to call the file, cats.php. I used the required ob stuff to do the include.
3. I tried to use chdir('forums'); to ensure I was in the forums folder where the file was located, but it gave an error because the file was in the forums folder already.
This seems so weird, I mean the file executes when called from the browser but if I try to call it within vB... vB throws the error.