We have one licensed copy of ESX Server.
I have ordered a second, for a second system.
I downloaded the ESX 3.5 software and burned myself a CD, and then applied for another eval license so I can install it while waiting for the license (our partner told me they can't even order them yet).
When I click on the "Activate Evaluation Now" it gets confused and alternately tells me that it can't verify my password, even though I was already logged in, or that the service is unavailable.
ESX 3.5 can run for 60 days in an unlicensed mode. this is fully functional.
Tom Howarth
VMware Communities User Moderator
Get a hold of licencing and they will either fix the one you currently have or issue you another eval license.
Hope that helped.