The problem with absolute paths is, well, that they are absolute! so moving your patch around your HD will cause it to stop loading your files.
I posted a solution to this some time ago. It is a small abstraction that generates absolute paths relative your main patch each time you open it. It does exactly what you are trying to do (except that instead of "open $1.wav, 1" you would send something in the lines of "open /subfolder/$1.wav, 1"