can anyone explain me this error:

...hitcounter table already exists. ...querycache table already exists. ...objectcache table already exists. ...categorylinks table already exists. ...logging table already exists. ...user_newtalk table already exists. ...transcache table already exists. ...trackbacks table already exists. Creating externallinks table...Query "CREATE TABLE `externallinks` ( el_from int(8) unsigned NOT NULL default '0', el_to blob NOT NULL default '', el_index blob NOT NULL default '', KEY (el_from, el_to(40)), KEY (el_to(60), el_from), KEY (el_index(60)) ) TYPE=InnoDB " failed with error code "Can't create table './wireless_wiki_1_5/externallinks.frm' (errno: 121) (localhost)".

greetz jhh