What's the alternative for my failing PHP code about block visibility based on user? I would like to remove certain blocks, so that admin can not see them.
In block visibility settings - in pages tab, I try to put followng php code but with no effect. (In user tab there is no php field to put code.)

&lt;?php 
if(arg(0) == 'administrator' )
return true;
else 
return false 
?&gt; 


What I am doing wrong?

EDIT: On my other D6 site I use argument: 

 user_access('access administration pages')


but on D7 site it does not work, what can be another way of doing it?
You could perhaps just set the "Roles" options under the block visibility settings.

Alternatively, something like:

global $user;
return in_array('administrator', $user-&gt;roles) ? FALSE : TRUE;