The most recent software can be found on the x10 software download page:
http://www.x10.com/support/support_soft1.htmYou have to enter the registration code sent to you by x10 when you purchased your software.
The latest version of iWatchMobile I see is 3.286.
You can verify your version by clicking Plug-ins, scrolling to the plug-in you want to check, and clicking about.
If you haven't registered, you should be able to bring up the registration box by going to Plug-ins, iWatchMobile, Register now, and enter your registration code.
Sometimes if you copy/paste the code from your email it will add spaces to the code and not work properly.
The best thing is to manually type the reg code into the box.