I didn't want to directly edit it, but the Configuration section instructions read:
Insert the following code after wfLoadExtension( 'CIForms' );
in LocalSettings.php (this facilitates setting the global variables listed below)
define( 'CIFORMS_VALUE_IF_NULL', 0 ); define( 'CIFORMS_VALUE_OVERRIDE', 1 ); define( 'CIFORMS_VALUE_APPEND', 2 )
That last line needs a closing semicolon (I think? w/o it it broke my site)