I'm spanish, so i'll try to explain clearly with my low english level...

Problem appears when you try to create an ''Online Player ID'' at ''GooTool''. This option is at the toolbar -Advanced/Online Player ID. so don't press it again!!!

I was trying to resolve the problem, since i found a solution:

1. DELETE THE FILES that i'm gonna put here:

-pers2.dat
in Windows XP:
C:\Documents and Settings\(your name)\Local Settings\Application Data\2DBoy\World of Goo\
in Windows Vista:
C:\Users\(your name)\AppData\Local\2DBoy\World of Goo\

-log files (delete all temporally files into Temp directory, all that is rubbish)
in Windows XP:
C:\Documents and Settings\username\Local Settings\Temp.
in Windows Vista:
C:\Users\username\AppData\Local\Temp.
Sometimes it might instead be in C:\Temp or C:\Windows\Temp. For Mac OS X and Linux, it's in /tmp/

-delete all files at the directory that you configure the first time you run GooTools too.

2. You must to uninstall/install ''World of Goo'', you'll lose all your progress, but game is shorty, so any problem to succes it again.
Uninstall/install ''GooTools'' as well (the uninstall.exe is found at the directory that is installed)

3. Run ''GooTools'', it must to run correctly, like me.

U can use addins, publish your profile... everything, but not press ''Online Player ID'' again, cause you'll crash the program against.
I hope this problem will be the common problem for everybody, and thanx for GooTools program and all the forum users! (''Of course World of Goo as well xD'')

World of Goo, a very veery good game... AMAZING! -Graphic Designer...

---> Please, report if this solution works to you...