Beagleboard memory test

I'm using beagleboad rev C3, Angstrom Linux version 2.6.29-omap1
(oe@OE-builder) (gcc version 4.3.1 (GC
C) ) #1 PREEMPT Thu Oct 1 13:48:21 CEST 2009

I ran memtester-4.1.2 compiled by arm-none-linux-gnueabi-gcc (Sourcery
G++ Lite 2008q3-41) 4.3.2.
I made a little change to memtester.c, otherwise it keeps test 65536
bytes.

            /* Try mlock */
            if (mlock((void *) aligned, bufsize) < 0) {
                switch(errno) {
#if 0 /* modified here */
                    case ENOMEM:
                        printf("too many pages, reducing...\n");
                        free((void *) buf);
                        buf = NULL;
                        wantbytes -= pagesize;
                        break;
#endif /* modified here */

The result shows a few failures as below. Does this mean memory on my
board is dead?
Or could it be a software issue? Has anyone seen similar thing before?

bchen@beagleboard:~/arma8$ ../../memtester 256M
memtester version 4.1.2 (32-bit)
Copyright (C) 2009 Charles Cazabon.
Licensed under the GNU General Public License version 2 (only).

pagesize is 4096
pagesizemask is 0xfffff000
want 256MB (268435456 bytes)
got 215MB (226009088 bytes), trying mlock ...failed for unknown
reason.
Continuing with unlocked memory; testing will be slower and less
reliable.
Loop 1:
  Stuck Address : ok
  Random Value : ok
  Compare XOR : ok
  Compare SUB : ok
  Compare MUL : ok
  Compare DIV : ok
  Compare OR : ok
  Compare AND : ok
  Sequential Increment: ok
  Solid Bits : ok
  Block Sequential : testing 61FAILURE: 0x3d3d3d3d != 0x3d3d3c3d
at offset 0
x00022e06.
  Checkerboard : ok
  Bit Spread : ok
  Bit Flip : ok
  Walking Ones : testing 30FAILURE: 0xbffffdff != 0xbfffffff
at offset 0
x00b8b805.
  Walking Zeroes : ok

Loop 2:
  Stuck Address : ok
  Random Value : ok
  Compare XOR : ok
  Compare SUB : ok
  Compare MUL : ok
  Compare DIV : ok
  Compare OR : ok
  Compare AND : ok
  Sequential Increment: ok
  Solid Bits : ok
  Block Sequential : testing 223FAILURE: 0xdfdfdbdf != 0xdfdfdfdf
at offset 0
x01513804.
FAILURE: 0xdfdfdbdf != 0xdfdfdfdf at offset 0x01513805.
  Checkerboard : ok
  Bit Spread : ok
  Bit Flip : stesting 185