I have the same problem...
My DSi firmware is 1.4...My card is an Acekard2i patched with the dannyphantom exploit...I was running AKAIO.1.4.1.PROPER_Repack_5-4-09 all backups loaded succesfully including "KingdomHearts"...I then undated to AKAIO.1.5...game loads then screen freezes white blank. M&L: Bowser's Inside Story loads fine, but now "KingdomHearts" won't load, along with many others. I attempted, M&L: Partners in Time and Castlevania POR, resulting unsuccesful...someone please advise.