NO_SPOOLFILE

XMail failed to allocate a file handle for this spoolfile.

Some possible reasons are:
- The number files inside your spool folder exceeds 
  the number of possible filehandles of your operating system.
- Some permission problem.
- The spoolfile was locked by another application.
- The spoolfile was deleted manually or by some filter.
  In that case the inspector shows an empty Spoolfile tab.
