[Lynne]

First look at line 4505 in profile.php (that is where the error originates as per your error message). My line 4505:

PHP Code:

eval('$HTML = "' . fetch_template($templatename) . '";'); 


So, it's something to do with the template on line 64 (also per the error). There is a hook right above there, profile_complete, so it could be a modification too. Try disabling your plugins and see if you still have this problem.
Note: To temporarily disable the plugin system, edit config.php and add this line right under <?php

PHP Code:

define('DISABLE_HOOKS', true);