I have a dell windows xp . I purchased (imatch) but can't get it 2 load the final step # 3 (artwork and remaining songs). I keep getting the itunes error 5.1.2600.6055

I have a Dell (Windows XP). I purchased (imatch) but can't get it 2 load all the way 2 step #3 (artwork and remaining music). itunes error (5.1.2600.6055) .

which tell me 2 up date 2 the latest version of itunes. I have the latest version already (11.0.2.26). So when i up date it doesn't finish. it keeps show there's an error and kick me out of itunes !!!