[horde] there are some notice line on the page

[Adrian Mak]

I install horde 3.0.7 and setup user authentication against on mysql db
backend. However I click around on the horde setup, I found there are some
notice on the page
e.g.
Notice: Only variable references should be returned by reference in *
/usr/local/php-4.4.0/lib/php/Log.php* on line *131*
Notice: Only variable references should be returned by reference in
/www/horde/lib/Horde/Form.php on line 322


What are these ??