errcode=-4 : Caused by not having the required loading data for that particular DS Normal game in infolib.
errcode=-5 : Caused by not having the required loading data for that particular DSi-Enhanced game in infolib and also caused by not having the 
             latest ttpatch.dat/r4patch.dat/m3patch.dat in the TTMenu folder (file depends on which cart you are using).
errcode=81 : File fragmentation on your microSD. Backup microSD to PC, then Full format with the Panasonic SD Formatter to rectify.
errcode=83 : Save file fragmentation on your microSD. Backup microSD to PC, then Full format with the Panasonic SD Formatter to rectify.