There is a "thea_path.txt" file in: "C:\Program Files\Google SketchUp 8\Plugins\TheaExporter_files\thea_path.txt" This file has to be deleted. When you start SU again you will be asked to select thea.exe from Thea's folder. On Win7 the "thea_path.txt" might be located in: "C:\Users<user>\AppData\Local\VirtualStore\Program Files\Google SketchUp 8\Plugins\TheaExporter_files\thea_path.txt" Anyway, using installer is the recommended solution.