Why does FP2000 ask for Usename & password twice?

[Bill]

In FP2000, on one of my websites, the first time I open a document in the FP
editor that uses shared borders, I'm asked for my username & password again.
Regardless of if I enter my username/password, or click "cancel", the page
opens normally with the shared borders.

I can open the shared borders themselves fine, no prompt.

This seems to be independent of the computer I'm using - I've got FP2000 on
two computers & same behavior.

Any ideas?

Thanks,

Bill.