Help with Log Errors: Unknown column 'entry_count' in 'order clause'

In module TargetLists, when I try to sort by “Targets in List”, I get a semi blank screen (no search fields, no list) and the following error in suitecrm.log:

Die 20 Dez 2016 15:16:43 CET [15683][7098c295-4ea7-26fe-af1d-4dda14b75350][FATAL] Query Failed: SELECT prospect_lists.id , prospect_lists.assigned_user_id , prospect_lists.name , prospect_lists.list_type , prospect_lists.description , jt0.user_name assigned_user_name , jt0.created_by assigned_user_name_owner , ‘Users’ assigned_user_name_mod, prospect_lists.date_entered , prospect_lists.created_by FROM prospect_lists LEFT JOIN prospect_lists_cstm ON prospect_lists.id = prospect_lists_cstm.id_c LEFT JOIN users jt0 ON prospect_lists.assigned_user_id=jt0.id AND jt0.deleted=0

AND jt0.deleted=0 where prospect_lists.deleted=0 ORDER BY entry_count ASC LIMIT 0,31: MySQL error 1054: Unknown column ‘entry_count’ in ‘order clause’

Any ideas?