From my two calls to support I've learned:
At least their first level support doesn't know what iTunes Match is.
- The first time, I was told that it would only handle songs that were in Apple's "master database".
- The second time, I was told that it only worked for songs purchased from iTunes
The other thing that drives me crazy, is they ask you for a phone number, in case they get disconnected, and then when you get disconnected, you never get a phone call back!
I had to go to the product page and read the description to these people.
One thing this latest support guy had me do is to turn off iTunes Match, deauthorize the computer, reauthorize the computer, turn on iTunes Match. While the songs didn't upload, it did cause them to go from "Waiting" to "Error".
I'm running on Windows 7 x64 using the iTunes 11.0.2.25 (64-bit). My PC is hardwired into a switch, which connects to a gigabit switch which connects to a WRT54GL, which is my gateway, DHCP server, and wireless access point.
I've tried different ISP's, different DNS servers. I even set up another PC with a fresh installation of Windows and iTunes, only to experience the same issue. The only thing I have not tried is wireless. I'm really not all that keen on doing so. I'm hooked up to a gigabit network for a reason, and moving to 54Mbps theoretical throughput is not going to work.