What does "Second Error signal from LINV1PD: 129" mean?

Hi, I'm using NM7.1.2 $EST MAX=9990 NOABORT NSIG=3 SIGL=9 PRINT=1 METHOD=CONDITIONAL LAPLACIAN SLOW $SUBR ADVAN6 TOL=6 Predictions are made using F_FLAG=0 and F_FLAG=1 I get this message I have never seen before. It happens with one particular model that is closely related to others that run Ok. The model with this error seems to run Ok and produces plausible parameters. What does this message mean? Second Error signal from LINV1PD: 129 Nick -- Nick Holford, Professor Clinical Pharmacology Dept Pharmacology& Clinical Pharmacology University of Auckland,85 Park Rd,Private Bag 92019,Auckland,New Zealand tel:+64(9)923-6730 fax:+64(9)373-7090 mobile:+64(21)46 23 53 email: [email protected] http://www.fmhs.auckland.ac.nz/sms/pharmacology/holford