Problem network with Parallels Desktop 8

Hi all,
i'm new in this forum.

I work in an Italian company (so sorry but I'm not very good at English, P) that bought in the last 6 months, several apple devices.

Were purchased: a macmini a device where I installed Parallels Desktop 7 and there were no problems.

and 3 imac 21.5'' where I have installed Parallels Desktop 8.

In version 8, we continued disconnections from the network that last 2/3 seconds.

The business software that we use can only be used on OS Windows, and every time I get disconnected from an error (the software does not parallels) and I block all operations, forcing me to go out and start all over again.

I followed several guides that are on the forum but I can not solve the problem, I did all the possible combinations of network configuration but I have not found a solution.

you know some other test to tell me?

thanks