ITunes Proxy Authentication & iTunes Store can't connect

Question

1) Stop Proxy Authentication Window
To solve the issue with the Proxy Authentication window coming up over and over please add the following to lines to your Proxy Configuration above the first DENY rule:
acl iTunes browser iTunes
http_access allow iTunes
2) Access Content in iTunes Store with Proxy
If you are having any issue with Content being displayed in the Store with Proxy, please follow the steps below:
In the Internet settings remove the tick next to "Autodetect" and "Proxy Server"
Launch iTunes and Connect to the Store (you should see no result when on Corporate network with Proxy)
in the Internet settings add the tick to "Autodetect" (or) 'Proxy Server" (set as you had before)
Launch iTunes and conenct to the Store, you should see content.
If you did above whilst on Corporate network with Proxy you will see badly rendered Content.
If you did above off Corporate network with no Proxy conencted to the Internet you will see the Store rendered correctly.
If you try this step once off the Corporate Network, the rendered content looks correct even when you connect to iTunes store via Proxy after the fact.

Answer 1

I have the same problem. The only firewall which I use is the wondoes firewall
Microsoft Windows XP Home Edition Service Pack 2 (Build 2600)
System manufacturer System Product Name
iTunes 7.5.0.20
CD-Treiber 2.0.6.1
CD-Treiber-DLL 2.0.6.2
Current user is an administrator.
Current date and time are 2007-12-27 21:25:50.
Info on the screen:
NVIDIA GeForce 7900 GS
** Network connectivity tests **
About Network Adapter
Adapter Name: (02E5BAB0-654B-4891-A2D6-D1EB7766ECA4)
Description: NVIDIA nForce Networking Controller - Packet Scheduler Miniport
IP address: 192.168.0.4
Subnet Mask: 255.255.255.0
Default Gateway: 192.168.0.1
DHCP enabled: Yes
DHCP server 192.168.0.1
Lease receive: Thu Dec 27 2007
Lease ends: Tue Jan 19 2038
DNS Server: 83,169,185,161
83,169,185,161
83,169,185,225
Active: LAN connection
Connected: Yes
With the Internet: Yes
Modem in use: No.
LAN in use: Yes
Proxy in use: No.
About Firewall
Windows firewall is activated.
ITunes is in Windows firewall enabled.
Connection with the Apple Web site has been successful.
Connection with the iTunes store had failed.
The network connection has been rejected.
Secure connection with the iTunes store had failed.
The network connection has been rejected.
The establishment of a secure connection to the iPhone activation server was successful.
I'm german so this is a translation with google, because I don't have time now, sorry