Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_10 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8E600 Safari/6533.18.5)
I had beta 4 iTunes until about 20 minutes ago, but my iTunes had been giving me that message since 122 hours before it was set to expire. Your only problem appears to be that your iTunes is still beta 4. Hence 10.5b48 or whatever, that is beta 4. Your phone should be fine, if it isn't, go back to 4.3.5 anytime.