Error message

[font=Arial]Hi all. I keep getting this message when I’m editing the actions on a button:[/font]
[color=sienna]The instruciton at “0x005363fd” referenced memory at “0x3f859530”. The memory could not be “read”.[/color]
[font=Arial]Any idea what means and why? [/font][font=Arial]Thanks[/font]
[font=Arial][/font]