To Mzabary:
If understand you, you have 2 PCs, configured identically, using the same DOS client both of them. They are doing the same tasks - therefore, they are accessing the same data files. One works fine, one gets the error message 2-3 times a day. You've replaced the PC (the whole thing) more than once but no fix. You've re-cabled the workstation. Correct so far?
More questions (some are obvious...) regarding the bad PC:
1.) Did there used to be a PC at this station that was working correctly? If so, what has changed - I mean ANYTHING?
2.) Explain what you did when your re-cabled the workstation - what part of the network did you re-cable?
3.) Have you swapped the two PCs between locations to see if the problem moves or not?
4.) Do you have access to any packet monitoring (or sniffing) equiptment to determine packet loss, noise, etc.?
Let's start by getting answers to these questions.
Bill