[Pellet-Users] Inconsistent ontology

[Alessandro]

When I check my ontology I get this error:
"DIG 1.1 (The language used to communicate with the reasoner) does not 
support hasValue restrictions on datatype properties. Ignoring 
restriction and attempting to continue."

on a class with this restriction
LO:Format has "mp3"
and LO.Format is a datatypeproperty with string as its range

Racer just warn about the problem, Pellet says "mp3" is inconsistent.

What can I do to solve the pellet inconsistence? Of course as Pellet 
consider the ontology inconsistent, it denies make inferences.
Thanks
Alessandro D'Ostilio