I use a function GetOpenFileNameMulti GetOpenFileNameMulti , but after select files and Klik open, i have an error Runtime, why?

I try to open more the one file with a function GetOpenFileNameMulti. Runtime error. What i should do in the function

  begin
      { Successful; user clicked OK } what should i write here
      { FileNameList contains the selected filename(s) }
      Page.Values[0] := File.CommaText; {List to String}
    end;