Delphi components in Builder 4

After purchasing Builder 4 pro in replacement of Builder 1 standard I realize
I may have made a "fatal error".
I had installed Delphi components in Builder 1's VCL and would like to reinstall
them in Builder 4. They are used by one of my projects, developped with Builder 1.

However I find that whenever I try to install a .pas file into the VCL, Builder compiles
whatever is in the component's "uses", such as "Windows.pas", "Messages.pas", SysUtils.pas"
etc. SysUtils.pas generates errors, and that's the end of the story.

An idea anyone?

Bernard Leprtre