foating point exception
 

I am working on an ejector system with fluent. this system has two inlets and one pressure outlet and the flow inside the ejector is supersonic. while i apply pressure inlet boundary conditions, fluent gives error as follows:
Divergence detected in AMG solver: ads-0
Primitive Error at Node 1: floating point exception
what can i do?
it is interesting to note that while i apply mass flow boundary conditions for inlets, there is no problem.