Problem with PHP on IIS

I run winxp using IIS 5.1 server, i installed the php binary and got it to work with the test script , however when i downloaded a script off the internet to try it can't write any files. I went on to try and give the write access to the specifying directories still nothing, i also changed the NTFS file permissions, maybe i'm doing it wrong or something like that. can someone tell me what i must do to get php to work properly? thx p.s. i tried that script on one of the free servers that supported php and it worked fine there.