I just fixed the same problem on my machine.
I had been running EQ2 on the laptop (crafting) with no problems lately. I finally decided to come back to the desktop and play some. The ProfitUI updater would never start (it ran fine on the laptop).
A comment earlier in this thread told me what I needed to do. My laptop uses Windows 7 and the standard firewall. My desktop uses Windows XP and I use ZoneAlarm as the firewall. Sure enough, somehow, ZoneAlarm had categorized the program Java(TM) Web Start Launcher to BLOCK instead of ALLOW.
Once I changed this setting, it runs fine on the desktop.
