minos_bran produces NaNs

[Chunli-Dai]

When n=81, l=83, the results from minos_bran are NaNs.
This problem occurs when I use the following input:
input model file:
../models/prem_noocean.txt
output file:
prem_noocean_S
eigenfunction file (output):
eprem_noocean_S
enter eps and wgrav
1.E-12 200.
enter jcom (1=rad;2=tor;3=sph;4=ictor)
3
enter lmin,lmax,wmin,wmax,nmin,nmax
83 84 0. 200. 81 81

It seems that in line 2957 of minos_bran.f, the denominator of a2 is zero. The same case
for a1.
The NaN value of wtry is then given to we(2) (Line 209), which cause infinite loop for the next degree l=84.

I'd really appreciate it if someone can fix this problem. It'll help me a lot. Thanks.