Index: lib/class.tx_commerce_product.php
===================================================================
--- lib/class.tx_commerce_product.php	(revision 50338)
+++ lib/class.tx_commerce_product.php	(working copy)
@@ -306,7 +306,8 @@
 	 * @return uid of category
 	 */
 	function getMasterparentCategory() {
-		return $this->conn_db->get_parent_categorie($this->uid);
+		$catArr = $this->conn_db->getParentCategories($this->uid); 
+		return $catArr[0];
 	}
 
 
Index: pi1/class.tx_commerce_pi1.php
===================================================================
--- pi1/class.tx_commerce_pi1.php	(revision 50338)
+++ pi1/class.tx_commerce_pi1.php	(working copy)
@@ -355,7 +355,7 @@
 					$this->product->setPageTitle();
 				}
 
-				$this->master_cat = $this->product->get_masterparent_categorie();
+				$this->master_cat = $this->product->getMasterparentCategory();
 
 				// Write the current page to the session to have a back to last product link
 				$GLOBALS["TSFE"]->fe_user->setKey('ses', 'tx_commerce_lastproducturl', $this->pi_linkTP_keepPIvars_url());