ADA compilation error

[tolkamp]

I have tried to compile my first small ADA program (Hello WORLD) using the GNAT GPS. See code below:
 
with Ada.Text_IO; use Ada.Text_IO;
procedure Hello is
begin
   Put_Line ("Hello WORLD!");
end Hello; 
 
After compiltaion the following error message is displayed:
 
gnatmake -u -q -gnats C:\Program\ Files\bin\hello.adb
fatal error, run-time library not installed correctly
cannot locate file system.ads
gnatmake: *** make failed.
 
process exited with status 4
 
 
What can I do to find system.ads?