Problems, Turbo Pascal 6 and Windows 95 (DOS mode)

I am working on an application which is made with Turbo Pascal 6 and Topaz
(for connection with DBase). This application contains 11 PC's with the same
program (Turbo Pascal 6), all these programs are using the same database
(DBase, on a network). With DOS everything is working OK. Now I am changing
DOS for Windows 95 and I have the following problem. Only one computer can
connect to the database. Every other computer, on which I want to run this
program an error message appears (error 150, problem opening index file).
This problem only occurs when I am working with a DOS box, when I restart in
the DOS mode everything is working fine.
Does anybody know how I can solve this problem ?