Just try open a TestRunner. You will get a DNU and that won't let you even debug the error.  

Pharo core version: PharoCore-1.2-12061

I attach PharoDebug.log

PluggableThemedOverflowPanelMorph(Object)>>doesNotUnderstand: #statusColor

Issue:� http://code.google.com/p/pharo/issues/detail?id=2717

Cheers

Mariano