Index: lams_common/src/java/org/lamsfoundation/lams/learningdesign/ScheduleGateActivity.java
===================================================================
diff -u -r2d3f325967701b692ee348165d1e6e1d0e73bed9 -r44df446bc6a02b35ba0bffc2bfa92ce78f80c763
--- lams_common/src/java/org/lamsfoundation/lams/learningdesign/ScheduleGateActivity.java	(.../ScheduleGateActivity.java)	(revision 2d3f325967701b692ee348165d1e6e1d0e73bed9)
+++ lams_common/src/java/org/lamsfoundation/lams/learningdesign/ScheduleGateActivity.java	(.../ScheduleGateActivity.java)	(revision 44df446bc6a02b35ba0bffc2bfa92ce78f80c763)
@@ -27,12 +27,16 @@
 import java.util.Date;
 import java.util.GregorianCalendar;
 import java.util.Set;
+import java.util.Vector;
 import java.util.TimeZone;
 
 import org.apache.commons.lang.builder.ToStringBuilder;
-import org.lamsfoundation.lams.learningdesign.exception.ActivityBehaviorException;
+import org.lamsfoundation.lams.learningdesign.dto.ValidationErrorDTO;
+//import org.lamsfoundation.lams.learningdesign.exception.ActivityBehaviorException;
 import org.lamsfoundation.lams.learningdesign.strategy.ScheduleGateActivityStrategy;
 
+import org.lamsfoundation.lams.util.MessageService;
+
 /**
  * <p>The hibernate object that wraps the information to schedule a gate in the
  * sequence engine. The schedule gate is defined either by offset to the
@@ -349,15 +353,16 @@
      * Validate schedule gate activity (offset conditions)
      * @return error message key
      */
-    public String validateActivity() {
-    	
+    public Vector validateActivity(MessageService messageService) {
+    	Vector listOfValidationErrors = new Vector();
     	if(isScheduledByTimeOffset()) {
     		if(getGateStartTimeOffset().equals(getGateEndTimeOffset()))
-    			return "flash.validation.error.illegalScheduleGateOffsetsType1";
+    			listOfValidationErrors.add(new ValidationErrorDTO(messageService.getMessage(ValidationErrorDTO.SCHEDULE_GATE_ERROR_TYPE1_KEY), this.getActivityUIID()));
     		else if(getGateStartTimeOffset().compareTo(getGateEndTimeOffset()) > 0)
-    			return "flash.validation.error.illegalScheduleGateOffsetsType2";
+    			listOfValidationErrors.add(new ValidationErrorDTO(messageService.getMessage(ValidationErrorDTO.SCHEDULE_GATE_ERROR_TYPE2_KEY), this.getActivityUIID()));
+    		
     	}
-    	return null;
+    	return listOfValidationErrors;
     }
     
     /**