my first guess, you have different number of cells on each side of the interfacenadd this line to the udf nMessage(
side 0 c0= %f
side 1 c1=%f , c0, c1);nyou should find some lines printed before it crashes and you can see that c0 and c1 are not equal ... if yes, my guess is rightnnif the number of cells are identical on the two sides, try calling this by the host, then pass the values to the nodes n