Alright so ... i followed this here xxxwiki.remote-exploit.org/index.php/HowTo:Set_up_a_USB_stick_to_save_changesxxx

worked first time great guide ... BUT... when im done with backtrack and want to go back to my other OS then go back to backtrack all this is the error i get on my SD card

mount: wrong fs type, bad option, bad superblock on /dev/sda2,

missing codepage or other error

in some cases useful info is found in syslog - try dmesg | tail or so

heres a pic of error and the dmesg | tail command
xxximg360.imageshack.us/img360/7/snapshot1in5.pngxxx

sorry cant post URLs remove the x's ^^