strange php API error

I've created a php extension that calls a shared object. This shared object makes a distributed call to a remote server. When I execute a web page which calls the function implemented by the php extension I sometimes receive a no reply from the server. Everytime I receive a zero byte reply the logs of the remote webserver show several distributed calls have been made from the server running php. It appears that the php engine is trying to run my code over and over again. This problem seems to occur only when I'm calling the function implementing the php extension from inside an object method. What is the best way to debug php extension problems? Has anyone ever executed a function implemented by the API and received no response from the server? Thanks, Tait