NO, you don't make the theme a format, leave the theme how it is...
did you format your usb drive using your xbox 360 & transferred a theme from your 360 to your usb memory? you just put that that them in the same folder as the one you transferred from your 360
first i configured my flash drive with my xbox, then i moved a theme "gun" to the flash drive. took the flash drive out put it in my computer. opened that usb gui program. clicked file, open device selector. clicked data partition, content, 0000000000, then clicked this "fffe07d1" which i a.ssumed was the theme. clicked that then clicked the 00030000. clicked in there and see "gun theme" so i dragged the jpg you gave me in there. saved that sh*t put it in my xbox and when i check the usb the jpg is a corrupt file