ITunes Store error msg: We could not complete your iTunes Store request. An unknown error occurred (-50).

Question

So I began having trouble connecting to the iTunes store with my computer about a month ago. It was working fine, I purchased and downloaded some music, and then the next day I got this message when I clicked on the iTunes Store: "We could not complete your iTunes Store request. An unknown error occurred (-50). There was an error in the iTunes Store. Please try again later."
Some basic facts about my computer:
Mac OS X 10.7.3, purchased in May '12.
iTunes is updated to the latest 10.6.3 version.
I have Sophos Anti-Virus (newly installed in the last two weeks).
No firewalls are set up.
Parental controls are not blocking anything (don't have them set up).
Internet connection is fine, no matter how I connect.
I did have an older version of iTunes (the previous version, so it wasn't that old) when the problem began, so I updated to the newest version hoping it would fix it; but it hasn't. I have checked the firewalls per apple community posts. I have checked the network connection. I only just put on an Anti-Virus (and the problem was pre-AV, so it shouldn't be that). I FINALLY figured out how to uninstall iTunes, and then I reinstalled it. The store still won't open, giving me the same message. 
A little more research seems to show that the (-50) error is when it times out? But the message appears barely half a second after I click on the iTunes Store icon. It doesn't seem to even try; there isn't enough time to warrant a 'timing out'.
I am at a loss. At this point I am considering taking my computer in and telling them 'fix it, no matter what', but if I can avoid the hassle of being without my one and only computer for at LEAST a week, that would be great.
Does anyone have any ideas?! 
Thank you and God bless!
Mary 

Answer 1

Hi Laura-Wedders,
Thanks for visiting Apple Support Communities.
On August 7th, some users may have been unable to make purchases from the App Store, iTunes Store, Mac App Store, or iBookstore. Apple worked quickly to resolve these issues, however you may have experienced them.
To check the current status of these systems please see:
Apple - Support - System Status
http://www.apple.com/support/systemstatus/
If you are still experiencing issues, you may want to troubleshoot with the following articles:
Can't connect to the iTunes Store
http://support.apple.com/kb/TS1368
iTunes: Advanced iTunes Store troubleshooting
http://support.apple.com/kb/TS3297
All the best,
Jeremy