In this case, the error can appear after changing the Application Panel settings.
- adding your own logo, changing the color etc.
- then reverting the settings and clic Reset Logo.
- after this whenever you try to connect with the Windows client (mstsc.exe) you get an error.
Line 15961 (File "C:\Program Files (x86)\TSPlus\UserDesktop\ApplicationPanel.bin"):
Error: Variable used without being declared.
- open the file ApplicationPanel.ini with a notepad, located in C:\Program Files (x86)\TSplus\UserDesktop
- delete this line: "logoffbutton=no" (or yes).
After changing the Application Panel settings, the server adds/changes the line "logoffbutton=no" (or yes) in ApplicationPanel.ini.