I have tried, all with no success:

• Different browsers.
• Different computers - one of which was not used to log on to United for months.
• Different IP addresses - I am pretty sure I had the same problem on the road.
• Using the parameters passed to the Web Site by the United.com person with whom I spoke and who successfully got to my e-upgrade summary.

This is really puzzling, and I hope someone posts what was happening when it is finally solved.