growisofs 6.1 fails to allocate shared memory beyond 16m

[Stefano Vesa <stefanovesa@tiscali.it>]

Hi everybody,
I'm running Linux 2.615 on a Slamd64 distro.
I've successfully compiled dvd+rw-tools 6.1.
If I launch growisofs as normal user no problem to allocate whatever size of 
the fifo buffer.
If I launch growisofs as root or I put it suid-root the max ring buffer I can 
allocate is 16m. It seems that also the growisofs default 32m value is too 
high for my system:

:-( unable to anonymously mmap 33554432: Resource temporarily unavailable

Obviously no problem if I type ulimit -l unlimited before launching growisofs.
Has my kernel or my bash too low limit values? There's a way to work around 
this problem without using ulimit?

If I type ulimit -a I get:

core file size        (blocks, -c) 0
data seg size         (kbytes, -d) unlimited
file size             (blocks, -f) unlimited
max locked memory     (kbytes, -l) 32
max memory size       (kbytes, -m) unlimited
open files                    (-n) 1024
pipe size          (512 bytes, -p) 8
stack size            (kbytes, -s) 8192
cpu time             (seconds, -t) unlimited
max user processes            (-u) 8191
virtual memory        (kbytes, -v) unlimited

TIA
Best Regards
Stefano