Override keyword doesn’t actually change anything, but not using it is the most common cause of this problem. It’s basically just a safety check to confirm you’ve spelled the function name and declared the parameters/qualifiers exactly the same in both the child and parent. So make sure you use the override keyword to confirm that you haven’t made such a mistake.
Failing that, the only other explanation is that your object is actually of type parent and not child.
[MENTION=71009]Philippe St-Amand[/MENTION]: You need to wrap in [code][/code] tags (without the underscores). Click the BBCode link at the bottom for info.