Well, I found the problem. I had previously been using the mining_proxy instance to mine lite coins and when I started using it for bit coins I just changed the -o parameter to slush's pool but I left the other parameters the same. To mine litecoins there is a -pa script parameter and having that still there caused the proxy to spit accepted messages but the pool ignored them. So the running command line for the mining proxy is:

python mining_proxy.py -o stratum.bitcoin.cz -p 3333

Sometimes I amaze myself by how dumb I can be.

Anyway, thanks to everyone who helped.

Morris