Pokemon Diamond, Pokemon Pearl and Age of Empires work perfectly and without errors on my Supercard DS ONE (without touching the patch options). The problem may be your microSD (I have 1GB/2GB Transcend).

Regarding the menu thing, you can L+Y (if I remember correctly) to make icons smaller up to the point of having a list, in 3 or 4 modes, so if you can´t manage to get on well with one, just switch to another

Also, It seems unnecesary to me that, if you have a Slot 2 Supercard and you can also browse it form the Slot 1, why not store the GBA games in the Slot-2 and everything else in the Slot-1? Seems logical to me.