"Fix for getNext/PrevAlphabetically when a fetchRow() returns null."

application/models/rows/CourseCode.php

@@ -20,7 +20,7 @@ class CourseCode extends Nmc_Db_Table_Row
         $where = implode(' AND ', $where);
 
         $row = $this->_table->fetchRow($where, $order);
-        if($row->getPrimaryKey()) {
+        if($row instanceof Nmc_Db_Table_Row && $row->getPrimaryKey()) {
             return $row;
         }
 
@@ -30,7 +30,7 @@ class CourseCode extends Nmc_Db_Table_Row
         $where = implode(' AND ', $where);
 
         $row = $this->_table->fetchRow($where, $order);
-        if($row->getPrimaryKey()) {
+        if($row instanceof Nmc_Db_Table_Row && $row->getPrimaryKey()) {
             return $row;
         }
 
@@ -39,7 +39,7 @@ class CourseCode extends Nmc_Db_Table_Row
         $where = implode(' AND ', $where);
 
         $row = $this->_table->fetchRow($where, $order);
-        if($row->getPrimaryKey()) {
+        if($row instanceof Nmc_Db_Table_Row && $row->getPrimaryKey()) {
             return $row;
         }
 
@@ -75,7 +75,7 @@ class CourseCode extends Nmc_Db_Table_Row
         $where = implode(' AND ', $where);
 
         $row = $this->_table->fetchRow($where, $order);
-        if($row->getPrimaryKey()) {
+        if($row instanceof Nmc_Db_Table_Row && $row->getPrimaryKey()) {
             return $row;
         }
 
@@ -84,7 +84,7 @@ class CourseCode extends Nmc_Db_Table_Row
         $where = implode(' AND ', $where);
 
         $row = $this->_table->fetchRow($where, $order);
-        if($row->getPrimaryKey()) {
+        if($row instanceof Nmc_Db_Table_Row && $row->getPrimaryKey()) {
             return $row;
         }