402.2.1260 IIS7 Windows Server 2008 R2 Web Service

I have a 3rd party webservice that runs by posting a soap message directly to a dll.

It runs perfectly on my development machine, but when I try and deploy it to Windows 2008 R2 64-bit using IIS 7 it fails, indicating error 404 2 1260 in the IIS7 log.

I have done all of the normal stuff, including:

• Setting the ISAPI and CGI Restrictions,
• Adding the Handler Mappings and setting them to Execute,
• Setting Handler Mappings Feature Permissions to Execute

but none of that helps.

When I enable Failed Request Logging, the lowest-level detail that I can get is:

• Error Code 0x800704ec
• Error Code 2147943660
• Error message IsapiModule This program is blocked by group policy

What is going on!?

The DLL was a 32-bit DLL.

By default, IIS 7 running on Windows Server 2008 R2 64bit doesn't allow 32bit dlls to run.

There's a little setting in the Application Pool Advanced Settings called Enable 32-Bit Applications. Set it to True in the application pool to which your web service belongs, and it should start working!