Office staff tried to replicate the issue, but in different browsers, the Region drop down refreshed just fine to the appropriate Netherland regions. I couldn't replicate the issue, either, but I did confirm that her region in the database shows as Alabama, while her country is Netherland. When I manually fixed the region in the database, she was able to proceed through checkout and her card processed.
I wasn't able to get as much information as I'd like from the customer, but she did provide that she was using Mac OS X and Safari (no version info for either, unfortunately). I've tested it using my version of Safari in Mac OS X, and couldn't replicate the issue. Has anyone heard of this? Anything I can do to isolate the issue?

I did a search and only found similar drop down issues relating to templates, but I'm on a straight OpenCart default theme, v. 1.5.5.1
I have a few plugins:
http://www.opencart.com/index.php?route ... on_id=5081
http://www.opencart.com/index.php?route ... on_id=6191
http://www.opencart.com/index.php?route ... ion_id=185
and a couple of vQmods:
Clear all Filters
Admin Filter Categories
Add All Zones
Any help would be appreciated!
-Ryan