Why do I get the error message ‘aspnet_wp.exe (PID: XXXX) was recycled because it was suspected to be in a deadlocked state ‘

This problem might occur because ASP.NET limits the number of worker threads and completion port threads that a call can use to execute requests.
For more details refer PRB: Contention, poor performance, and deadlocks when you make Web service requests from ASP.NET applications

You could control the deadlock detection by changing machine.config setting in

<processModel responseDeadlockInterval='...'  ... />