I'm using Prince 8.0 with a PHP 5.3.10 web application running on IIS on Windows Server 2003. Use authenticate to the web application using Windows authentication (set in IIS); Basic authentication has been disabled.

Whenever a user tries to convert a document, it results in a 500 error. When I test it while logged in using my Windows account, it works, presumably because I have administrative rights on the server. Would Windows authentication cause this problem? The IIS AppPool user is the default Network Service account. How is the prince.exe process called in PHP? Thanks!

The Prince executable is called from PHP using proc_open(). Is there a security permissions setting in IIS controlling which executables a PHP page can access?

I got this solved. I had to give the anonymous IIS user read and execute permissions to "C:\Windows\System32\cmd.exe." I abandoned the Windows authentication in the application in favor of querying the LDAP database instead. Thanks for the help!

For the record, Prince 10 now has support for Windows authentication.