"Unable to start program" When debugging .NET CF on windows CE 7

I am developing a project for Windows CE 7 using .NET CF 3.5, developing on VS 2008 SP1 Starting at some time point (cannot recall any special issue) i cannot debug any more. I can launch the program and run it, but when trying to debug i get: "Unable to start program '......\Arowce7tp.exe'. An error occurred that usually indicates a corrupt installation (code 0x80004002). if the problem persist repair your visual studio installation ..."

• i changed deployment locations on the device
• I uninstalled/reinstalled the VS 2008
• uninstalled/reinstalled the SDK
• I regsvr32 all applicable DLLS

I CAN launch the application without debugger (CTRL-F5), i cannot debug it - only on this computer !!

thanks