Avast 4.8 blocking network application

Hello: I am running Avast 4.8 Standard Suite on a server and client pc’s.
Server is running Win2000 Advanced Server, PC’s are all XP Pro.
Server is also running the Distributed Network Manager Console.

I have an application (Structural Materials Manager) that is installed on the server an is run from the client PC’s.
It uses a usb security lock to manage the number of licenses. The usb security lock is on the server. It sends a heartbeat to the client pc’s to let them know of the license availability.

It was working fine before I installed Avast.
It was working fine after I installed Avast Home Edition on a client pc to test it.
It is not working properly since I installed the purchased version of Avast Standard Suite 4.8.
I can launch/run the Structural Materials Manager app directly from the server. However, when I launch the application from a client pc, it displays a security error in that it can’t find the usb lock. Avast seems to be blocking it, and I am at a loss.

In the administration console>client-side tasks>on-access scanning tasks, there are several providers listed. Which provider would be blocking the security application? If I am looking in the wrong area, please let me know.

Thanks for your help, and I look forward to your reply,
Vince

None of them should do that.
So, I can only say - try stopping them one by one and see if anything helps.