DECLARE vCustomerHostName	  VARCHAR(255) DEFAULT NULL;
DECLARE vOldHostAcknowledged      int(11) DEFAULT NULL;

#COMMENT See if Host has been Acknowledged
  SELECT CASE WHEN EXISTS(
    SELECT 1 FROM nagios_objects NdoObjs
    JOIN nagios_acknowledgements NdoAcks on NdoAcks.object_id = NdoObjs.object_id
    WHERE name1 = vCustomerHostName
    AND name2 is null)
  THEN 1 ELSE 0
  END AS HostAcknowledged INTO vOldHostAcknowledged;

Gives Error:
Illegal mix of collations (ascii_general_ci,IMPLICIT) and (latin1_swedish_ci,IMPLICIT) for operation '='