If you are working with Microsoft Project Professional 2010 and Web Application 2010 with local regional settings other than US-English you may experience problems when trying to open multiple projects from Project Center in Project Professional 2010. The bug has been reported to Microsoft, who are now working on a fix to solve the issue. Meanwhile the only way to solve the problem is to open the projects manually in Project Professional by inserting them into a masterplan or changing the local regional settings to US-English.