Go the LabVIEW forum and search for "occurred", browse through the answers. Then repeat the action with "occured", and you'll see a few more.
On my LV 2012 (we will skip 2013...) I still have some VIs that spit "occured", e.g. Exception occured in Microsoft OLE DB Provider for ODBC. not sure if this spelling error is still present in 2013.