dot -Tps sub.dot > test.ps produce a nice core dump on my system. the exact and only message returned by this command line is:

Abort (core dumped)

Actually, it aborts in routespl.c.
#0  0xdfac66ac in _libc_kill () from /usr/lib/libc.so.1
#1  0xdfa8a71a in raise () from /usr/lib/libc.so.1
#2  0xdfa7b824 in abort () from /usr/lib/libc.so.1
#3  0x80869ea in routesplines (pp=0x8109d60, npoints=0x8046a94) at routespl.c:181
#4  0x807bc51 in make_regular_edge (edges=0x8115620, ind=48, cnt=1) at splines.c:761
#5  0x8079871 in dot_splines (g=0x80f75e0) at splines.c:266
#6  0x8072a29 in dot_layout (g=0x80f75e0) at init.c:247
#7  0x80590f0 in main (argc=3, argv=0x80470ec) at dot.c:49

However when I try to generate a GIF from the .dot file dot -Tgif sub.dot > test.gif there's no problem at all and there should be no difference between gif and postscript execution at the place where dot aborts in routspl.c
Input file: b57.dot
Owner: north
Status: Fixed