I've recently been experimenting with implementing a pool and testing it against GUIminer. To my surprise, it was not able to handle paths in URL of the pool, only subdomains. For example, calling:

http://tpbitpool.appspot.com

on port 80 gives a proper response of

{'message': 'Method not found', 'code': -32601, 'data': 'The called method was not found on the server'}

But calling

http://tpbitpool.appspot.com/anything

Or even

http://tpbitpool.appspot.com/

Despite being able to be handled by the server, gives an error of

"Problems communicating with bitcoin RPC"

Testing the same URLs with Python's jsonrpc gives correct results.

Is there any reason why a miner would behave in this way? Is there a list of mining software that behave similarly?

(note, the above URL should be up for some time for testing purposes, but reachable only via http and https ports)