"error backing up iphone (-43)" when updating to ios 5

[CHAM89]

I've been trying to update to ios 5 all day, but when attempting the update every time I get an error message when itunes is backing up my phone, that says "error updating iphone (-43)" and gives me the option to cancel or continue without backing up. When I manually back the phone up, everything runs smoothly and it backs up but I get this error while trying to install ios5. My phone is currently running 4.2.6 and is jailbroken with greenp0ison. Is this error related to the jailbreak? if I continue without the update process backing up will a manual back up file work once ios5 is installed? Thanks for any help