Help regarding montecarlo analysis of an Inverter

 Hello all,

I am runing a montecarlo simulation for an inverter.I have got an expression from calculator determining the propagation delay and I have passed it on to ADEXL for montecarlo analysis .The problem is ,the delay expression is not evaluated by montecarlo showing an error although the simulation runs.
The delay expression which I exported from the calculator is ((delay(?wf1 v("/vin1" ?result "tran-tran") ?value1 0.5 ?edge1 "rising" ?nth1 1 ?td1 0.0 ?wf2 v("/Z<1>" ?result "tran-tran") ?value2 0.5 ?edge2 "falling" ?nth2 1 ?td2 0.0 ?stop nil ?multiple nil) + delay(?wf1 v("/vin1" ?result "tran-tran") ?value1 0.5 ?edge1 "falling" ?nth1 1 ?td1 0.0 ?wf2 v("/Z<1>" ?result "tran-tran") ?value2 0.5 ?edge2 "rising" ?nth2 1 ?td2 0.0 ?stop nil ?multiple nil)) / 2)