This is most likely a problem with your dumped nand, In my time of using triiforce and now this, I've noticed you get errors like that if your missing something it needs on the nand itself, even a BLANK empty folder, If its missing.. Errors out
Compatibility seems to change based on what type of nand dump you did as well, I've even heard it go so far as some games work but you need a save game of it on the dumped nand prior to playing.
On a side note I've tested rev17 and rev21 with this app, I have not tested all games with each so i cant speak of any compatibility differences, all games i tried work with both. But i did notice the fastest base with rev21 was 38, all others took much longer to get game list, however rev17 was literally 2x faster getting game list/booting the game. 228 games, 7 sec to load with r17 and 14 with r21 base 38 and 22 with rev21 base 57...just thought id report my findings.
Also WiFi does NOT work with any base of rev21, incase anyone still wondered