Occurrence of ghostbands (From Wien Maillist )

Ghostbands occure for two reasons:

 a) the energy parameters are not set properly. This means most of the time
   that the wien2k-defaults for your system (mainly due to the required RMT
   values or due to a particular charge transfer) are not good. In most cases
   it comes because for ONE atoms there are 2 expansion energies for the same 
"l",
   and these energies are too close.
b) The sphere sizes are too different. This happens in particular when a cation
   (like your Na or Ca) has too large spheres compared to H, O, B. Often such
   ghostbands appear for (partly) converged calculations.

Reference: http://www.mail-archive.com/wien%40zeus.theochem.tuwien.ac.at/msg09842.html