diff --git a/main/document/showinframes.php b/main/document/showinframes.php
index 48a0142724..ec1ea3cfce 100755
--- a/main/document/showinframes.php
+++ b/main/document/showinframes.php
@@ -169,7 +169,7 @@ header('Pragma: no-cache');
 $browser_display_title = 'Documents - '.Security::remove_XSS($_GET['cidReq']).' - '.$file;
 // Only admins get to see the "no frames" link in pageheader.php, so students get a header that's not so high
 $frameheight = 135;
-if ($is_courseAdmin) {
+if (api_is_course_admin()) {
     $frameheight = 165;
 }
 
diff --git a/main/exercise/admin.php b/main/exercise/admin.php
index 6e2e865db6..0f3494abb9 100755
--- a/main/exercise/admin.php
+++ b/main/exercise/admin.php
@@ -110,8 +110,10 @@ if (isset($_REQUEST['convertAnswer'])) {
     Session::write('objQuestion', $objQuestion);
 }
 $objAnswer = Session::read('objAnswer');
+$_course = api_get_course_info();
 
 // document path
+
 $documentPath = api_get_path(SYS_COURSE_PATH).$_course['path'].'/document';
 
 // picture path
diff --git a/main/inc/lib/api.lib.php b/main/inc/lib/api.lib.php
index 6bfa90a213..10709fd45c 100644
--- a/main/inc/lib/api.lib.php
+++ b/main/inc/lib/api.lib.php
@@ -1432,6 +1432,10 @@ function _api_format_user($user, $add_password = false, $loadAvatars = true)
 {
     $result = [];
 
+    if (!isset($user['user_id'])) {
+        return [];
+    }
+
     $result['firstname'] = null;
     $result['lastname'] = null;