why does my network connection time out when downloading iphone 4 software update?

Not sure, but how are you connecting to the internet? Is it a wireless connection? If so, try a wired connection.

I'm having the same problem. Tried both wireless and wired connections. Can't update ipad, ipod touch or ipod nano either. Keep timing out

I'm having the same problem too. I cannot sync or update over wireless or wired connections ever since I installed the most recent iTunes update. iTunes goes through the complete OS 5.0.1 download only to tell me the connection has timed out just when it seems ready to install. I've since reinstalled iTunes, I've ejected and done hard restarts on both my problem devices. I've disabled anti-virus, anti-malware, and firewall. No change in outcome except that, after doing all this, my final attempt to simply sync my 1st Gen iPad led to iTunes crashing and being automatically closed by windows just before finishing the final step. Is this a cruel joke, because I'm certain I can hear iTunes laughing at me for wasting so much time on this.

Windows 7, 64-bit

iPhone 4 with iOS 5.0

iPad 1 with iOS 5.0

This is a common issue when downloading updates, literally hundreds of postings about this.

Temporarily disable any Anti-Virus and Firewall software on the computer.

Okay, it turns out that you're half right. Despite having already disabled as many features as I could find in my anti-virus protection, I was still getting the time out. Finally, I completely uninstalled AVG 2011.

Problem solved!

I had switched from one anti-virus provider to another not long before updating iTunes. So, wheras McAfee seems to operate just fine, AVG blows it. So, stay away from that one. Even disabling it didn't keep it from interfering with iTunes.