UnManaged Call from Web Service on IIS 7.0

Hello - I'm trying to call an unmanaged dll from a web service on IIS 7, Windows 64 bit. When I run it from Visual Studio everything executes properly, but when I access it via the localhost the webservice throws a 500 error. I've changed the web site to be 32 bit compatible and changed the app pool to use Network Service but it still seems like a permission error. Any ideas on what needs to change to get this to work on IIS 7? Everything works fine using IIS 6. Public Shared Function GenerateLicenseNow(ByVal inLicense As String) As String Dim pDll As IntPtr = NativeMethods.LoadLibrary("C:\Inetpub\LicenseWS\rsilicgen_11_6.dll") 'oh dear, error handling here 'if (pDll == IntPtr.Zero) Dim pAddressOfFunctionToCall As IntPtr = NativeMethods.GetProcAddress(pDll, "GenerateLicense") 'oh dear, error handling here 'if(pAddressOfFunctionToCall == ...