this is normally found in the the DelphiProjectsDir/BPL
for delphi 7 it's "c:\Program Files\borland\Delphi7\Projects\Bpl"
when not changing the standard directories
if you have the .bpl, you don't need to recompile the package
you can install it from the .bpl file directly (providing it's the correct bpl/delphi version) using component/install package
change the dropdown to .bpl
in your .dpk you can also set a output directory and other directories, like for searching dependant units
if these directories are changed then these compile errors can happen