ORIGINAL: da berzurkur yea I did that at first with just the re-scan failed & existing plugins options checked but still no love until I reset all...
Project5 comes with a nice little utility called the Plugin Manager. Run \Plugin Manager\PMInstall.exe from your installation Project5 DVD to install it. The plugin manager will let you enable/disable individual plugins as well as manage plugin settings. By disabling an offending plugin you may be able to then open your project. This provides a clean and safe way to manipulate plugins.