You didn't get the code of the module fleet_maintenance from the right place (I guess you got it from the extra-addons). You should get the code from lp:fleet_maintenance ; it works very well on OpenERP 6.1 (and crm.case has been removed in the current code).
You didn't get the code of the module fleet_maintenance from the right place (I guess you got it from the extra-addons). You should get the code from lp:fleet_maintenance ; it works very well on OpenERP 6.1 (and crm.case has been removed in the current code).