Genesis Tabs require Genesis on theme switch.

plugin.php

Index: trunk/plugin.php
===================================================================
--- trunk/plugin.php	(revision 1791008)
+++ trunk/plugin.php	(working copy)
@@ -144,7 +144,7 @@
 
 					echo '<div id="cat-' . $cat . '" '; post_class( 'ui-tabs-hide' ); echo '>';
 
-						if ( ! empty( $instance['show_image'] ) ) :
+						if ( ( ! empty( $instance['show_image'] ) ) && ( function_exists( 'genesis_get_image' ) ) ) :
 							printf( '<a href="%s" title="%s" class="%s">%s</a>', get_permalink(), the_title_attribute( 'echo=0' ), esc_attr( $instance['image_alignment'] ), genesis_get_image( array( 'format' => 'html', 'size' => $instance['image_size'] ) ) );
 						endif;