subscribe2 problem

I installed subscribe2 yesterday and activated it. Then when I went to options –> subscribe2 in the admin page everything looks fine until I get to the bottom right under where is sais “Exclude categories”. There it displays the error “Warning: Invalid argument supplied for foreach() in XXXXX/wordpress/wp-content/plugins/subscribe2.php on line 407”

then whenever I click submit to try to submit my changes to the options I get the error “Fatal error: Call to undefined function: update_categories_cache() in XXXXX/wordpress/wp-content/plugins/subscribe2.php on line 704
“

So far the plugin works fine, I just cant change any of the settings because I keep getting those errors and the settings I change don’t get saved. So I either need to fix the errors or else I need to know how I can manually change the settings I want.

Any help would be much appreciated.