Hi, Chris.

>When I run my Web Service class from VFP (i.e. load an instance of the class and make calls into it's member functions without going through the IIS manager) the program works correctly. I can tell it to open a file e.g. IF FILE(CcApplicationPath+"ARDATA\ARCUST01.DBF") USE (CcApplicationPath+"ARDATA\ARCUST01.DBF") IN 0. (Where CCApplication path is #defined perhaps, or read from a table perhaps).
>
>But that same IF statement when calling the Web Service via IIS returns .F. to the test for the file - it cannot "see" the DBF. I have tried substituting drive letter and directory (e.g. "S:\PRO65\") with the correct UNC name (e.g. "\\SERVER\PRO65\") but it makes no difference.

Have in mind that the user which the Web Service impersonates is IUSR_[your machine]. You can check the actual username in your IIS console.

Be sure that this user has access to the data directory.

Hope this helps,