I'd like to know what the php error is all about, though 2.4.6 was rock solid and it may be a conflict from another plugin (just a guess). Using
save="1" should allow the link to be shown even if it's not shown by default. But there is also a setting to show it only for logged in users, so depending on what that was set to, you may not be able to override it.
It's possible to change the settings via direct database edit, but you need to know what you're doing or else WordPress is in a big mess. I'd suggest you need access to the settings page, whether by fixing the php error or installing the current version of the plugin, if the simple edit above doesn't work.