The blue site is the original KeyGenius website, which has since become depricated in favor of the green site, which is actively being maintained and is hosted by Yubico (I know this is confusing, and I will put up a notice on the blue site about this). Thw two sites each have their own database and are completely separate. If you store a password on the blue site, it will not come up on th egreen site and vice versa.
The Greasemonkey script contains a variable pointing to the server it should use, thus what may be happening is that you have one computer set up to use the blue site, and one set up to use the green site. You can check this by right-clicking on the Greasemonkey icon, selecting Manage, clicking on KeyGenius in the lists of scripts, then clicking on Edit. This will open the script in a text editor, and one of the first lines contains the server (it starts with "var server = ").
An alternative to installing Greasemonkey and the script, is using the KeyGenius bookmarklet. For information on that, either watch
this video by John Salter, or take a look at the
Getting Started section of the FAQ.
Once you've successfully stored a password, it should work the same regardless of which computer you are using, as long as all computers are set up to use the same KeyGenius server.
Good luck, and please let me know if you have any further issues.
Regards,
Dain