Inserted missing validator notify callback object

code/MathSpamProtectorField.php

@@ -47,7 +47,8 @@ class MathSpamProtectorField extends SpamProtectorField {
 
 	/**
 	 * Validates the value submitted by the user with the one saved
-	 * into the {@link Session}
+	 * into the {@link Session} and then notify callback object 
+	 * with the spam checking result.
 	 *
 	 * @return bool
 	 */
@@ -55,6 +56,15 @@ class MathSpamProtectorField extends SpamProtectorField {
 		if(!self::is_enabled()) return true;
 
 		if(!self::correct_answer($this->Value())){
+			$validator->validationError(
+				$this->name,
+				_t(
+					'MathSpamProtectionField.INCORRECTSOLUTION',
+					"Incorrect solution to the spam protection question, please try again.",
+					PR_MEDIUM
+				),
+				"error"
+			);
 			return false;
 		}