Seems there's some server CPU problems... Spark(H.P.I.C.) posted this today, as a new "global" announcement sticky at the top:
"We're experiencing server slowdowns lately, so I'm limiting the most CPU intensive part of the forums, searching, to those that have a paying membership here. This is a temporary measure until I can pursue some alternatives."
Questions? Comments? Go to Service & Support.
... And yes, I've been getting those 'server busy' messages a lot today as well.