iTunes version 9.0

[Blades_fan]

When I accessed iTunes on Saturday,a pop-up message advised me that an upgrade to version 9.0 was available,I downloaded it but ever since I cannot access iTunes Store.
I'm getting error message "we could not complete your iTunes Store request.An unknown error occurred (-50)."
My internet connection is ok,if I click on iTunes help tab and click check for updates it says "This version of iTunes (9.0) is the current version,and if I click on Run Diagnostics everything comes back ok.
Can anyone help?
Thankyou in advance.

[Mobius1]

A similar problem happened when I updated to version 9 of iTunes the other week. I couldn't understand why it wouldn't allow me to download the update for my iPod Touch, or why I couldn't connect to the Store even though my net connection was fine. It works again now, although I'm not sure what went wrong. I did try a few things though, and they may help you.

Firstly, try running the Apple Software Update client. This is separate to the "check for updates" feature in iTunes. You can usually find it under Start > All Programs > Apple Software Update. Run it, and see if it recommends any further software. Note that "Safari" is an optional download and not required for iTunes to work.

Make sure that iTunes is listed as an exception in your Windows Firewall (located in the Control Panel). If it is under the list of allowed programs, untick it, accept, and then go back, tick it again and accept again. This can sometimes refresh the Firewall's list of allowed programs. If, after rebooting, neither of these have solved the issue, try power cycling your broadband modem by turning it off and then back on again after a minute or so. Sometimes refreshing the settings of these devices can solve small issues like this.

Report back if you still can't connect to the Store.