No Disk Error

Hey, i just bought a u3 drive, I decided to go with portableapps instead. I look up how to get rid of u3 system but keep the autorun system. so i replace the u3 iso with my custom one, and it worked. but when i plug it in, it reads the autorun then it brings up a "no disk" error. but if i hit continue it brings up my appmenu anyway. any ideas?.