Undefined Index Errors after Turning On WP Super Cache

Hi,

Never had this problem before on the same host. Have had great success with the plugin – thank you!

Install and plugin activation go smoothly, however once I turn on caching I get these errors on the admin page.

Top of options page:
Notice: Undefined index: wp_cache_key in /…/wp-content/plugins/wp-super-cache/wp-cache-phase1.php on line 255

Below Title:
Notice: Undefined index: wp_supercache_cache_list in /…/wp-content/plugins/wp-super-cache/wp-cache.php on line 296

Below cache contents:
Notice: Undefined index: listfiles in /…/wp-content/plugins/wp-super-cache/wp-cache.php on line 1504

Any ideas? Not sure why this site is behaving differently.

Thanks!