After every one of the 29 results I have returned so far, the "result" of the network performance test has been exactly 100. This must mean that the test is failing to complete for some reason. I am, however, getting points for the results.

The same thing happens at home (in the Phoenix metropolitan area in the US state of Arizona, where my ISP is AT&T DSL Service) as in my dorm room at Caltech (which is basically its own ISP). That pretty much eliminates the ISPs as a possible cause of the issue. The connection at home is accessed over 802.11g wireless, and the connection at Caltech is accessed over 100Mbps Ethernet. I chose DSL as the answer to the question about connection type when I registered the agent.

I have already given the UD agent a DEP opt-out, since that is necessary for WUs to run correctly at all.

I can't see my software firewall (McAfee Personal Firewall Plus) nor the firewall in my home router (WRT54G) blocking anything coming from WCG, though this is based on the assumption that the relevant IP address(es) is (are) numerically close to those of the WCG website. For unrelated reasons, I tried doing various forms of tweaking using TCP Optimizer, but nothing changes the symptom at hand. I have taken my best efforts to make sure that the drivers for my network hardware are up to date.

My system specs are as follows:

1.86 GHz Pentium M
1 GB dual-channel DDR2 RAM
256MB NVIDIA GeForce Go 6800 video card
80 GB 7200 RPM hard drive
Windows XP Home Edition w/ OEM-installed SP2
McAfee SecurityCenter suite (VirusScan, Personal Firewall Plus, and SpamKiller are installed)
Spy Sweeper version 5.0

Any suggestions on how to fix this? For example, do I need to tell my firewall to trust certain IP addresses?