I won't be surprised if I don't get many replies to this. In the first place, it involves the dreaded IIS7 web server. In the second place, it's a real puzzler.

I've got two separate C5 sites running on IIS7. They each are configured as separate web sites (other than the default), and each have their own IP address. They were both set up in IIS7 exactly the same way. Both sites are using C5 5.5, though I also tried it with 5.4, and got the same thing.

One installed with no errors and runs with no errors.

The other one cannot install because it's throwing the following error:


They both are using the exact same PHP via FastCGI handler.

They both are running under the exact same system account, therefore both have exactly the same privileges in the system.

If one site is throwing errors, shouldn't the other one as well?

What I have tried so far:

- Double-checked to make sure both sites were using the exact same php handler, and it pointed to the same php executable. Check.

- Added all the IIS system accounts to the session.save_path directory. Results: no change.

- Created another directory, gave all the IIS sytem accounts read/write access to it, and pointed session.save_paths there. Result: the good site broke and started throwing the same error. The bad site continued throwing the same error.

The fact that one site is working perfectly, and another isn't seems to suggest something different between how the two sites are set up, but I have exhausted all the possibilities I know of.

Any ideas would be greatly appreciated, and thanks in advance for any effort made to reply.