Various "Undefined" notices on content admin screen
Try this, check to make sure it's set first:

&lt;?php if (isset($field_twithandle[0]['value'])): ?&gt;
&lt;a href="http://twitter.com/&lt;?php print $field_twithandle[0]['value']; ?&gt;" class="twitter-follow-button" data-show-count="false" data-show-screen-name="false"&gt;Follow @&lt;?php print $field_twithandle[0]['value']; ?&gt;&lt;/a&gt;
&lt;?php endif; ?&gt;


The problem is that those values aren't set on some pages, which is why you're getting the error. So that's a fix for an undefined index error. You also have things like undefined variable, for which a fix could be like:

&lt;?php if (isset($messages)): ?&gt;
  /* Do stuff here with $messages */
&lt;?php endif; ?&gt;