Issues with Simulation

Dear All, Recently we were running some simulation/estimation using SUBPROBLEMS in NONMEM 7.2. In these runs we were generating covariates using a random distribution such as the following: IF(ICALL.EQ.4) THEN COV1 = function + range*PHI(ETA(5)) COV2 = function(COV1)*EXP(ETA(4)) ENDIF TVKA = THETA(1) KA = TVKA*DEXP(ETA(1)) TVCL = THETA(2)*(COV2/X)**THETA(7) TVV = THETA(3)*(COV2/X)**THETA(8) The NONMEM run completes, but a TABLE file is not output and the following error is reported 0PROGRAM TERMINATED BY NP4F PRED RETURNS DIFFERENT OUTPUTS WITH THE SAME INPUTS MESSAGE ISSUED FROM TABLE STEP How do we avoid this error and get a table file? We looked at the archive, and found that Dennis Fischer had asked this question previously, but we did not see any follow-up on how to solve the problem. I do not remember having this issue with previous versions of NONMEM. Can anybody provide a solution to this problem? We would greatly appreciate it. Best, Matt