Sorry for bumping this up, have been pretty busy with school...
Finally got InstalledCodec to work (actually it did work the first time but I didn't realize that because it changed ArcSoft Audio Decoder HD to ArcSoft Effect Decoder HD when I disabled the former but I misread) and with the help for GraphEdit I disabled all the codecs that caused Img-Burn to error me: the two mentionned above, all versions of Franhoffer, another generic one. Finally, "MP3 Decoder DMO" is the one that worked (it shows up in green in GE for some reason). Now, I just want to make sure that won't break anything in my other applications, since I've disabled 4-5 MP3 codecs (so far so good in video games and in my foobar2k).
This might be useful if someone has a similar issue and is searching the forums!
Thank you for pointing me in the right direction UK! and great program too