This is a problem with the Borland export makefile and happens in the IDE–>Export makefile as well, but I thought I would share my work-around in hopes that you may be able to improve this task in FinalBuilder…
If you export a makefile some file names (in my case PATHCPP) may include spaces which cause the makefile to fail when building. I am using a script to wrap the file names with quotes unless they already exist. Unfortunately that gives me a multiple step process of using FB to create the makefile through the compile C++ builder project action (which fails as expected), running a script to fix the makefile, and then running make from execute program action.