most likely, it's because the file has the extension .FFP, and that file type is associated with TLH, so it opens the file with that program. Rename the file to have the .TXT extension, and you should be able to open it up in notepad (of course, if you already created the .torrent file, you'll either have to rename the file back to .FFP, or recreate the .torrent file to include the new TXT file).
alternatively, you might be able to just right-click on the .FFP file, and choose "open with notepad", or something like that. At least, that works in XP, I'm not sure about Windows 7.