Domain Verification - Yahoo Internal Server

Yahoo is throwing an "Internal Server Error" error when I try to create a new project and then verify the domain.

The page:
https://developer.apps.yahoo.com/dashboard/verifyDomain.html

The error:
Domain Verification Failed
Internal Server Error

The setup:
OSX 10.6.6 + Safari 5.0.3.

Note that the domain I specified is an IP address. Maybe that is causing the problem ?