Publishing failure in newly configured DITAOT2.1 in KC 2016

Hi developers,

 

I have configured DITAOT2.1 in KC2016. While publishing PDF it is throwing error like below.

Attribute "ishlabelxpath" must be declared for element type "bookmap".

Anybody can help me where I a doing wrong in configuring DITA OT and output format?

Thanks in Advance
Roopesh