database prefix: missing table node_revisions

An error appears when we look into revisions and have prefixed database: (in my case it_)

Error:

* user warning: Table 'konferencje4.node_revisions' doesn't exist query: SELECT COUNT(*) FROM it_node n , (node_revisions nr LEFT JOIN conference c on nr.vid = c.pvid AND nr.nid = c.pnid) WHERE n.type='conference_paper' AND nr.nid = n.nid in /sites/all/modules/conference/conference.module on line 2492.
* user warning: Table 'konferencje4.node_revisions' doesn't exist query: SELECT n.title, nr.uid, c.ruid, nr.log, n.nid, nr.timestamp, nr.vid, c.rnid FROM it_node n , (node_revisions nr LEFT JOIN conference c on nr.vid = c.pvid AND nr.nid = c.pnid) WHERE n.type='conference_paper' AND nr.nid = n.nid ORDER BY nr.timestamp DESC LIMIT 0, 25 in /sites/all/modules/conference/conference.module on line 2492.

Solution: (line 2489)

$sql .= " FROM {node} n , ({node_revisions} nr LEFT JOIN {conference} c on nr.vid = c.pvid AND nr.nid = c.pnid)";