When you attempt to open a pdf file with Acrobat reader using the AP Sublaunch command, you may get an error "File not found". If you check the pathname to the document (using the Open document command) and it proves to be valid, it is then very likely that there are spaces in that pathname. Removing the spaces should cure the problem. Interestingly enough, if the pathname to the Acrobat Reader application includes spaces it has no effect.