Spice simulation problem (option pivot)

Hello,

I'm simulating a Sigma-Delta modulator in Hspice and I get the following error:

*error*: maximum conductance on node 0:ecompar =( 0.0000D+00) is less than pivtol. check hookup for this node. set option nopiv and rerun.

I set .option NOPIV and rerun, but still get the same message. I am using voltage controlled sources as opamps :

*************************** Rin in integr_n 1k $interg_n =>negative input of intergrator's opamp Eintegr compar_n 0 OPAMP GND integr_n $compar_n =>negative input of comparator's opamp Cint integr_n compar_n 30p Rintegr integr_n fdb 1k $fdb =>feeback from the latch Ecompar latch_in 0 OPAMP GND compar_n MAX=5 MIN=0 ***************************

the rest of the circuit is 8 mosfets implementing a latch.

Does anyone have any idea why I get this message, and why setting the option NOPIV is ignored??

Thanks

George ( mail: giorgos.puiklis at gmail.com)