You might try the newest version of the Neo-Max software,here:http://www.neoflash.com/forum/index.php/topic,1871.0.html(forgot how to post a link

)
It will format the cart,whereas the NPK software will not.(I think..)
That should be the end of it,but I'll also mention-
That rom screwed one of my SD cards(for a short time-It made it unreadable to a particular menu version)
I am convinced that rom did the damage,and no one else I know of has had this issue,so it's nice (not nice,but,you know)to hear of someone else with a similar issue.
EDIT-Even just use Neo-Max to format,then go back to NPK if you need to......