It is likely something went wrong during upgrade. Try patching it again using the method described on http://xeams.com/ManuallyPatching.htm . Use the following method to restart Xeams:

• Open an SSH terminal to QNAP
• Ensure Xeams.jar and webfront.zip is copied in to the patches folder as described in the article
• Run the following command:
  wget http://localhost:5272/FrontController?operation=restart

If this does not work, extract webfront.zip into a TEMP folder and copy *.jsp to /share/CACHE_DEV1/.qpkg/Xeams/webfront/webapps/ROOT folder.