The Sound Output Mode has no 'High' option. It has 'None (fastest)', 'Digital Mono (fast)' and 'Digital Stereo (slow)'. Setting it on one of the latter two could help. As could setting the NDS Cartridge Backup Media to 'Flash 512k' or 'Auto'.
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No$GBA Quick FAQ:
Q1: Savegame doesn't load.
A: Set correct save type. Look
here, divide by 8!
Q2: "Cannot Read Data" error
A: See above!
Q3: Snapshots?
A: Only work for GBA games.
Q4: NDS linking, NDS with GBA slot, Picto-Chat, trading, ...
A: Not yet available.
Q5: When do we get a new version?
A: We don't know. Martin won't tell.
Q6: Donation down?
A: Yes, and we can't do anything about it either.
Q7: Game stops without appearent cause.
A: Turn the Sound option on.
Q8: No$Zoomer fixes don't work.
A: They do only with 2.6a.