I'm getting this message on a WP 3.2.1 install with PHP version 5.2.17
Notice: Undefined index: filter in /home/netstewp/public_html/wp-includes/default-widgets.php on line 382
Any idea why?
That a Notice, not an error. Turn off notices in your PHP installation, or turn off the WP_DEBUG mode.
More importantly, turn off display_errors. The display_errors setting should never, ever, be enabled on a production site. That's for debugging only.