Error coding an on click event for a button

[dfspannie]

  When trying to code an on click event for a new button on a form I get the following error :

E:\lazarus\lcl\lclclasses.pp(32,38) Error: unit not found: WSReferences

The program runs without a problem, showing the form and button. I just cannot code an on click event for the button.

Please assist.
Thanx.

[ivan17]

open the options dialog;

• verify that laz dir is properly set everywhere; replace e:\lazarus with E:\lazarus
• (environment>rescan fpc source directory;  retry method creation)
• back in options dialog, verify the fpc version (#.#.#) in paths - you may have upgraded to 2.4.3 but paths may still contain 2.4.0
• (environment>rescan fpc source directory;  restart;  retry method creation)
• if problem persists, empty the e:\lazarus dir and reinstall

oh and next time, search the forum - there is no point in someone typing this every week...