The directory name is invalid. cc

I have just recently installed php on windows 2000 running IIS 5.0. on two different machines. the first went flawlessly. The second seemed to proceed just the same, however, I have a problem. I created the standard test: <?php phpinfo(); ?> this works fine. when i hit the refresh button on my browser, i get back a simple if completely useless message: The directory name is invalid. more specifically, the message is : "<html><head><title>Error</title></head><body>The directory name is invalid. </body></html>" I have no idea what is generating this error. I have the same php.ini on both systems, the same security settings the same directory structure, I think the same configuration in IIS, but it only works on one installation! Thanks for any pointers you can give me. Chad Cotton