Applications not running when using network login

[musictech]

I'm having huge problme using certain applications with networked non admin account. The problem is we have a number of Macs running software such as Pro Tools, Reason, Logic etc. The software is stored and ran from the local HDs. Our Macs are integrated into a Windows server environement and our users log into their network accounts using active directory. This causes a few problems, the main one being that Pro Tools unexpectedly quits on occasions, and will not launch software instruments such as sampletank, nor will it run Reason 3.0 in rewire mode - Reason begins to load and then reports an error that it can't find the Reason engine. Then when we try to relaunch Reason it says that the Reason engine is already in use. Reason will work as a standalone piece of software but it will not work within Pro Tools. The other problem I have is that the local HD drives become read only when network users are logged in, users can only save to their network home directories. We are running OSX 10.4.10, Reason 3, and Sampletank SE, I have updated Pro Tools to version 7.1cs10. All software works fine with local users, I don't know whether I have to change some permissions, but I could really do with some help.