WCF / ASMX :: Second Request To Webservice Is Not Handled?

I have a Asp.net webservice. This webservice uses a dll ( the purpose of the dll is to listen at a port say 3305 and accept the request from one of its client (say client is some name PG and this client is different from webservice client) and the dll keeps communicating to the PG client to get some data.)

The webservice works like this.

When a request comes from my test program to Webservice, the webmethod calls the dll api ( to establish the connection between the dll and PG client). and after the connection is established between dll and PG client, the webmethod uses the data from my test program and implements some business logic and then returns some values to the test program.

After the first request from my test program is processed, the connection between DLL and PG will still be existing so as to serve the subsequent request from the test program.

The problem is after the first request is finished, the second request is not being processed by webservice, the request doesnot come to the webmethod or even to the class constructor.

is the connection between the DLL and PG , hanging up the webservice?