Yes it is exactly the same error.
Warning: in_array() [function.in-array]: Wrong datatype for second argument in /home/site.com/plugins/system/sourcerer.php on line 224
I am doing the following:
Adding the following code:
{source}
<?php
echo('This text is placed through <b>PHP</b>!');
?>
{/source}
to any component.
For example in the "Miscellaneous Information:" for a contact (default component in Joomla). e.g
http://demo.joomla.org/1.5/index.php?option=com_contact&view=contact&id=1:name&catid= 12:contacts
I get the same error with my own custom components when trying to use sourcerer but the contact component is a good example using the default Joomla 1.5 install.
Under Advanced Parameters>Security Settings for Components I have yes selected and enable only in check box ticked for everyhting (including contacts).
Do you need any other information?