UseSystemPasswordCharacter error

i m using vs2008

when i click on the text prperty of UseSystemPasswordCharacter=True then it create a error " files has invalid value " and a square box.

i am uninstall all program like ( VS2008, SQL, OS uninstall) then install all prog. but still not working.

first time click on run button it gives error then second time click on run button it runs the program

next time when run the prog it will be appear.

so how to remove this error.