In order to get it to work for 64bit you need to change:
code:
"REG QUERY "HKLM\SOFTWARE\Patchou\Messenger Plus! Live" /v AppDir 2>NUL | FINDSTR REG_SZ > TEMP.BAT" 
 with 
code:
 REG QUERY "HKLM\SOFTWARE\Wow6432Node\Patchou\Messenger Plus! Live" /v AppDir 2>NUL | FINDSTR REG_SZ > TEMP.BAT