Fatal error: Allowed memory size

the following issue has come up and I am not sure what the problem is. This is the massage:
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 73012 bytes) in /home/parchme1/public_html/main/includes/menu.inc on line 965

It changes as i try to do something different. For example, this happened today when I changed some modules, turned some off, and then when I save the changes, it gives me this error. I then go and try to up load a image to a node and bam another massage like this comes up and then the image never gets up loaded. If I go to the line that it is refrencing it is not logical to me what the problem is wit the PHP.

962 * Helper function - compute the real cache ID for menu tree data.
963 */
964 function _menu_tree_cid($menu_name, $data) {
965 return 'links:'. $menu_name .':tree-data:'. md5(serialize($data));
966 }
967
968 /**

So what on earth does the return links have any thing to do with the memory. When I do something else then yet another obscure error comes up. This is not logical to me.

Please help. The last post that I put up was utterly ignored.

Cheers
Jacob Melnick