Index: t3lib/class.t3lib_befunc.php
===================================================================
--- t3lib/class.t3lib_befunc.php	(Revision 7150)
+++ t3lib/class.t3lib_befunc.php	(Arbeitskopie)
@@ -2545,17 +2545,19 @@
 				}
 			}
 			$preUrl = $preUrl_temp ? (t3lib_div::getIndpEnv('TYPO3_SSL') ? 'https://' : 'http://').$preUrl_temp : $backPath.'..';
+
+				// check if we need to preview a mount point
+			t3lib_div::requireOnce(PATH_t3lib . 'class.t3lib_page.php');
+			$sys_page = t3lib_div::makeInstance('t3lib_pageSelect');
+			$sys_page->init(FALSE);
+			$mountPointInfo = $sys_page->getMountPointInfo($id);
+			if ($mountPointInfo) {
+				$id = $mountPointInfo['mount_pid'];
+				$addGetVars .= '&MP=' . $mountPointInfo['MPvar'];
+			}
+
 			$url = $preUrl.$viewScript.$id.$addGetVars.$anchor;
 		}
-	
-			// check if we need to preview a mount point
-		$sys_page = t3lib_div::makeInstance('t3lib_pageSelect');
-		$sys_page->init(FALSE);
-		$mountPointInfo = $sys_page->getMountPointInfo($id);
-		if ($mountPointInfo) {
-			$id = $mountPointInfo['mount_pid'];
-			$addGetVars .= '&MP=' . $mountPointInfo['MPvar'];
-		}
 
 		return "previewWin=window.open('".$url."','newTYPO3frontendWindow');".
 				($switchFocus ? 'previewWin.focus();' : '');