Same unit in different packages

Hi all
I have recently installed the Delphi and C++ builder on my system. I am facing a problem with the software; whenever I try to load the package, I see the following error message on my screen which reads:

I installed two packages, package X and package Z. Both packages contain a unit Y.
Whenever I try to compile the packages, it gives me an error.
Has anyone else encountered such a problem? If you know the solution please let me know. I am worried.
Waiting for your replies
Regards
Jerry
