PHP Warning: Invalid argument supplied for foreach() in /home/padtvro/public_html/wp-content/themes/claudia/content.php on line 30

The error is generated by this code:

line 27 $tags = get_the_tags();                     
line 28
line 29                    $cn_sidebar="";
line 30                    foreach($tags as $tg_id) {

If a post has no tags, get_the_tags() wil return false. Then supplying false to the foreach statement will get you the error mentioned. In order to prevent this you should wrap the foreach in if (!empty($tags)) { foreach ...}.