Segmentation Violation with NLINLSQ

[Peter <peter_hueckel(at)yahoo.de>]

Dear reader,
I am using NLINLSQ.PRO from the ISML Math.. in PV-WAVE as a fitting
routine.
Sometimes my program stops due to an segmentation violation. It gives
the following message:
% NLINLSQ: Terminal error: MATH_REMAINING_ELMNTS_NOT_ZERO
        "r(2,2)" = 0.000000e+00.  Remaining elements for the row must
also be ze
ro, but "r(2,3)" = -1.123467e-07 is not.
% ERROR: Signal encountered: Segmentation violation.
% Since this may indicate a serious problem, it is recommended you save
  all data and restart PV-WAVE.
% Execution halted at NLINLSQ <nlinlsq.pro( 123)>  (MATHSTAT_163).
% Called from FIT_FERMI <fermi_fit.pro(  22)>.
% Called from FIT_ROI <fit_roi.pro(  62)>.
% Called from TC <tcmapfit3_256_fermi_both.pro(  75)>.
% Called from $MAIN$ .

I would like to know how i can avoid this error or what is the reason
for it to apear. With some datasets it never happend and with some very
often.
Is there somebody who can help me with this?
Thanks.