I also cannot start Worldbuilder. I'm using Win7 32-bit. I have installed VC++ and VS2010 and .Net 4 Framework. I got the latest patch. ModBuddy, Fire Tuner and Nexus work fine. But when I try to run Worldbuilder, I get an error just after the window appears and then it closes. I don't see any complaints like this in other forums, so I don't know what's going on.