Index: typo3/sysext/install/updates/class.tx_coreupdates_migrateworkspaces.php
===================================================================
--- typo3/sysext/install/updates/class.tx_coreupdates_migrateworkspaces.php	(revision 9994)
+++ typo3/sysext/install/updates/class.tx_coreupdates_migrateworkspaces.php	(working copy)
@@ -99,7 +99,7 @@
 		$this->includeTCA();
 
 			// install version and workspace extension (especially when updating from very old TYPO3 versions
-		$this->installExtensions(array('version', 'workspaces'));
+		$this->installExtensions(array('extbase', 'fluid', 'version', 'workspaces'));
 
 			// migrate all workspaces to support groups and be_users
 		if ($this->isOldStyleAdminFieldUsed()) {
Index: typo3/sysext/workspaces/ext_tables.php
===================================================================
--- typo3/sysext/workspaces/ext_tables.php	(revision 9994)
+++ typo3/sysext/workspaces/ext_tables.php	(working copy)
@@ -2,8 +2,8 @@
 if (!defined ('TYPO3_MODE')) {
 	die ('Access denied.');
 }
-
-if (TYPO3_MODE == 'BE') {
+	// avoid that this block is loaded in the frontend or within the upgrade-wizards 
+if (TYPO3_MODE == 'BE' && PATH_typo3_mod != 'install/') {
 	/**
 	* Registers a Backend Module
 	*/