cant backup ipad, please read

I wish to upgrade to ioss 5. I play infinity blade, and i have red that the game is saved, and transfered back to ios 5. To do this i have to backup, but I CAN'T.

Everytime i want to backup i see the massage: itunes could not backup *******iPad. The backup cannot be saved on this computer. I havent backed up in a long time. I've thried everything.

DELEATE EXISTING BACKUP,

DELEATE THE BACKUP FILE IN THE BACKUP FOLDER,

USE A NEW CABLE,

USE A NEW USER ACCOUNT,

RESTART PC AND HARD RESTART THE IPAD,

REINSTALL ITUNES,

RESET THE LOCKUP FOLDER,

ENCRYPT BACKUP,

DELEATE PHOTOS,

DELEATE VIDEOS,

MAKE SHURE I HAVE ENOUGH DISK SPACE,

WAITED FOR TOMORROW,

DOSABLED THE AUTO SYNC...

Now it sometimes seas, that the device cannot start the backup, or that it cannot load something from the sync server........

PLEASE HELP ME.

Thanks