seems like you dropped the cache table in your database. try to access the db via phpmyadmin and check it out manually if its really "gone"
if: execute following SQL string:
CREATE TABLE `cache` (
`cache_id` varchar(32) NOT NULL default '',
`cache_language_id` tinyint(1) NOT NULL default '0',
`cache_name` varchar(255) NOT NULL default '',
`cache_data` mediumtext NOT NULL,
`cache_global` tinyint(1) NOT NULL default '1',
`cache_gzip` tinyint(1) NOT NULL default '1',
`cache_method` varchar(20) NOT NULL default 'RETURN',
`cache_date` datetime NOT NULL default '0000-00-00 00:00:00',
`cache_expires` datetime NOT NULL default '0000-00-00 00:00:00',
PRIMARY KEY (`cache_id`,`cache_language_id`),
KEY `cache_id` (`cache_id`),
KEY `cache_language_id` (`cache_language_id`),
KEY `cache_global` (`cache_global`)
) TYPE=MyISAM;
not sure if its the standard cache table - maybe i already extended it with a contrib.
good luck