Server process exited with status 139

I am consistently getting "Server process exited with status 139" whilst
trying to create a straightforward index - "Create index test1 on
voter(name);"
The table has 13 million records, and the longest name in the VARCHAR field
being indexed is 47 characters.

My system:
ABIT BP6, 2 x Celeron 500, 256 MB, 2GB swap
Gentus (ABIT) Linux - a version of RedHat 6
gcc 2.91.66
Kernel 2.2.18 patched with Raid and IDE patches
Postgresql 7.1 b4.1 installed from RPMs. (Same error occurs with
b3.2)
SORT_MEM=10000, shared buffers as default
SHMMAX,SHMALL = 33554432

An 870MB core dump is created:-

GNU gdb 4.18
Copyright 1998 Free Software Foundation, Inc.
warning: core file may not match specified executable file.
Core was generated by `postgres: p'.
Program terminated with signal 11, Segmentation fault.
Reading symbols from /usr/lib/libz.so.1...(no debugging symbols
found)...done.
Reading symbols from /lib/libcrypt.so.1...done.
Reading symbols from /lib/libnsl.so.1...done.
Reading symbols from /lib/libdl.so.2...done.
Reading symbols from /lib/libm.so.6...done.
Reading symbols from /usr/lib/libreadline.so.3...done.
Reading symbols from /lib/libtermcap.so.2...done.
Reading symbols from /usr/lib/libncurses.so.4...done.
Reading symbols from /lib/libc.so.6...done.
Reading symbols from /lib/ld-linux.so.2...done.
Reading symbols from /usr/lib/gconv/ISO8859-1.so...done.
Reading symbols from /lib/libnss_files.so.2...done.

#0 0x4014f117 in memcpy (dstpp=0x41958028, srcpp=0x40266a14, len=845964621)
at ../sysdeps/generic/memcpy.c:55
55 ../sysdeps/generic/memcpy.c: No such file or directory.

(gdb) bt
#0 0x4014f117 in memcpy (dstpp=0x41958028, srcpp=0x40266a14, len=845964621)
at ../sysdeps/generic/memcpy.c:55
#1 0x80662d5 in DataFill ()
#2 0x8066e8c in index_formtuple ()
#3 0x8077642 in btbuild ()
#4 0x8138a16 in OidFunctionCall5 ()
#5 0x808aeea in index_build ()
#6 0x8089d44 in index_create ()
#7 0x80a7030 in DefineIndex ()
#8 0x80fc0bc in ProcessUtility ()
#9 0x80fa325 in pg_exec_query_string ()
#10 0x80fb386 in PostgresMain ()
#11 0x80e5be5 in PostmasterMain ()
#12 0x80e579c in PostmasterMain ()
#13 0x80e4b96 in PostmasterMain ()
#14 0x80e4636 in PostmasterMain ()
#15 0x80c6bee in main ()
#16 0x401081eb in __libc_start_main (main=0x80c6b30 <main>, argc=1,
argv=0xbffffd44, init=0x80655a4 <_init>, fini=0x81437bc <_fini>,
rtld_fini=0x4000a610 <_dl_fini>, stack_end=0xbffffd3c)
at ../sysdeps/generic/libc-start.c:90

Do you think I simply don't have enough memory? I can use this pc to create
indexes on bigger datasets than this using Visual Foxpro or even Oracle/NT
bloatware!

Any help would be gratefully received. Thanks.
Jeremy Young