Dear Adrain Zhou,
you have found a bug. I assume you are having this problem when working
with a 64-bit executable. Please apply the following patches to rlbfgs.F:
Before line 538, insert this line:
INCLUDE 'irat.inc'
Change line 545 from
MSGLEN = 4
to
MSGLEN = 8/IRAT
Best regards,
Salomon