Fix exception in `HeaderUtil` during setup

diff --git a/wcfsetup/install/files/lib/util/HeaderUtil.class.php b/wcfsetup/install/files/lib/util/HeaderUtil.class.php
index e7671f0d238ef71164775aa46fea3711bc73f980..4985bd5acbc4f634fdc4b16bf2bca312faa62a65 100644 (file)
--- a/wcfsetup/install/files/lib/util/HeaderUtil.class.php
+++ b/wcfsetup/install/files/lib/util/HeaderUtil.class.php
@@ -55,7 +55,7 @@ final class HeaderUtil {
                @header('Content-Type: text/html; charset=UTF-8');
                
                // send no cache headers
-               if (!WCF::getSession()->spiderID) {
+               if (PACKAGE_ID && !WCF::getSession()->spiderID) {
                        self::sendNoCacheHeaders();
                }