Windows 7 64bit program freezes opening Network File

We bought a new Dell XPS 8500. We connected it to our file server which we are using a file server with Windows 2003 Server.

I am using a program called Strucad V15.5.

Basically, it is a 3-D modelling program. The model is stored on the server. If we store the model on the local machine the program and model opens up in about 2 secs if that.

If I open a model folder stored on the server, the program freezes at about 50% open every time.

I turned the network card down to 5 meg half duplex and I got the model to open up but it takes 3-4 minutes.

Can anyone suggest something or know how to fix this?

Thanks in Advance!!!