Then you have a version of the bootloader that isin't working on the 1.44 DSi, since the alex rider storm breaker is for the 1.41 DSi, while for the 1.44 Dsi it should have a Deep Labyrinth - Digital Bros icon.
You're only option is to try and find someone with a DSLite who would update the Acekard bootloader for you, using the file I linked to you.
You should also check what kind of HWID version you have, if it's "44", then you're only remaing option would be to buy a new flashcart.
Unfortutanetly I can't help you more then that since I have a 3Ds, which has already been updated to it's latest firmware, so you're Acekard wouldn't work on my 3Ds.