clockworkmod backup error on 902
i updated to 5.9.902 and remained rooted. i wanted to backup the stock rom before i flash anything else. when i tried to backup it gives me an error messagesaying it failed to backup /data and to open rom manager to report the issue. i open rom manager and there is no option to view or report the error. i viewed the recovery log and it says "W: unable to get recovery.fstab infor for /sd-ext during fstab generation"
then it has a lot of code and at the end it says "error while making backup image of /data! result was null, message is: assert failed:backup_rom("emmc/clockworkmod/backup/stockrooted:)
it shows that a backup is was mane and is available for restore but im iffy about using it. this is my first problem backing up with clockworkmod and im clueless. any ideas?