SanTLee, just to clarify you do not require the users module condition. Also, given we're checking two conditions for a true result we could still refactor it into a single condition which is good practice. For example:
<?if($USERS_ON$ && $USER_LOGGED_IN$)?>User Logged In<?endif?>
Again, however, you do not require the $USERS_ON$ condition either when checking $USER_LOGGED_IN$ or user conditions without an else statement given the output won't default to anything other than a false/null result of the condition function.
Clyde, glad we got to the bottom of the problem I'm going to close this thread for now. PM me if you need it reopened.