DSTT worked on mine but not friends

I am relatively new to this but computer savvy. I made a friend of mine, several friends actually, the DSTT cards with v1.16 and tested it on my DS they all worked fine. I shipped them out and they all say they won't work on their DS. This is the process I use. I DL v1.16 and put the files in a folder. I DL some ROMS and put them in a different folder. I loaded the menu files and one game and tested it out, worked fine. I then loaded several games, about 20ish. And randomly checked them out, worked fine.
I did this to four dstts.
They received them and it loads the DSTT screens properly but when the select a game it goes to loading, without doing a save file first. They asked about the games having a lock symbol on them but we tried a game without it and still the same.Anything I did wrong. The one I have works fine and it was created the same way. Is there a trick to get it working? Three of them have DS's that are about a year old and one has a brand new DS , I have a brand new DS as well. All are lite models.Help please

Hmm, you're not supposed to put the firmware files in any folder, just the root, so maybe that's what you meant. Try getting the MicroSDs back and see if they're locked by any permissions like Read-Only etc.?

I didn't load them onto a file on the micro card, that was where I put them on the computer when I DLed them. They are in the root on the micro card. The wierd part is it worked n my machine but not on there's. Could it be that I loaded all the games on the micro card on the root drive, I didn't create a folder for them

Okay good. No the ROMs do not need to be in any sort of folder, they can be placed anywhere on the MicroSD.