You are using custom paths, as such you will have to modify scripts to use those paths instead of defaults. look for the download.php file and consider this:
if(!stristr($_SESSION[MYAP]['vfile'],$_SESSION[MYAP]['vpath']) && !stristr($_SESSION[MYAP]['vfile'],'/var/spool/asterisk/monitor/fop2')) {
die("no way");
}
If the filename is not in /var/spool/asterisk/monitor/fop2 the script will abort right there. So you will need to modify to suite your needs/paths. Also, it is possible that the web server user is unable to read that file/path, so double check permissions.