This will likely be down to the folder structure, it sounds like the folder name is correct as it detected 'snes'.
In the template, do you have your library path as:
/romm/library/roms = /mnt/usr/path/to/roms
or
/romm/library/ = /mnt/usr/path/to/roms
If it's the first of the two, your folder structure should be:
/mnt/usr/path/to/roms/snes/snesgame1.sfc*
*or .zip