I worked it over with following path assignments:
Include path:..\colorx;..\colorado;$(BCB)\include;$(BCB)
\include\vcl
Library path:..\colorx;..\colorado;$(BCB)
\projects\lib;$(BCB)\lib\obj;$(BCB)\lib
BPI/LIB output:C:\Programme\Borland\CBuilder5
\Colorado\LIB\