I don't understand what "file" you are talking about.
To run games with DM(L), you need only one file : the game ISO.
on Wii :
* install BC v6 (maybe that's your problem!)
* install DM or DML 2.11
* Connect the drive to USB Port 0
* If you connect to USBPort1, DO NOT CONNECT any HDD on port 0.
on external (usb or sd):
* place your ISO in /games/game title here/game.iso
* place your launcher here in /apps/my favorite launcher/boot.dol
restriction for USB :
* HDD must not be bigger than 2TB
* HDD must not use Advanced mode (4096bytes/sector), Only 512bytes/sector works.
* Partition need to be the first physical partition of your drive (if your drive is partitioned, games need to be on the FIRST primary partition of the drive)
* Partition table need to be MBR (not GPT)
* Partition need to be primary (not extended/logical)
* Partition need to be formated to FAT32
* Cluster size need to be 32kB or less.
restriction for SD:
* same as USB, but usually SD card are not partitioned (but it can be done! so maybe your SD card is wrong, format it again with Panasonic SD Formater 4)
* FAT32
* 64k/cluster or less
Could you try to use USBLoaderGX instead of DM Booter?
USBLoaderGX will check your setting and warn you if something is wrong.
check here for full setup of DM/DML for USBLoaderGX
http://gbatemp.net/threads/usb-loader-gx.149922/page-878#post-4889738