cacti doesn't generate images

Hi, i just installed cacti-0.8.6 in a linux box using cent-os 4.3 the
problem is that cacti is not generating any images. when i turn on
graph debugging i get

RRDTool Command:

/usr/local/rrdtool-1.2.12/bin/rrdtool graph - \
--imgformat=PNG \
--start=-86400 \
--end=-300 \
--title="CORE ROUTER LPZ - Traffic - PO4/0/0" \
--rigid \
--base=1000 \
--height=120 \
--width=500 \
--alt-autoscale-max \
--lower-limit=0 \
--vertical-label="bytes per second" \
--slope-mode \
DEF:a="/var/www/html/cacti/rra/core_router_lpz_traffic_in_11.rrd":traffic_in:AVER AGE
\
DEF:b="/var/www/html/cacti/rra/core_router_lpz_traffic_in_11.rrd":traffic_out:AVE RAGE
\
AREA:a#00CF00:"Inbound" \
GPRINT:a:LAST:" Current\:%8.2lf %s" \
GPRINT:a:AVERAGE:"Average\:%8.2lf %s" \
GPRINT:a:MAX:"Maximum\:%8.2lf %s" \
COMMENT:"Total In\: 0 bytes\n" \
LINE1:b#002A97:"Outbound" \
GPRINT:b:LAST:"Current\:%8.2lf %s" \
GPRINT:b:AVERAGE:"Average\:%8.2lf %s" \
GPRINT:b:MAX:"Maximum\:%8.2lf %s" \
COMMENT:"Total Out\: 0 bytes"
RRDTool Says:

sh: /usr/local/rrdtool-1.2.12/bin/rrdtool: Permission denied

but the rra directory is registered to cactiuser and every one has the
privileges for running rratool.

I had trying changing all files in the cacti directory to be owned by
cactiuser and I have given all the files rwx privileges.

Here is a listing of the files in the rra directory:

drwxrwxrwx 2 cactiuser cactiuser 4096 May 23 17:11 .
drwxrwxrwx 11 cactiuser users 4096 May 23 16:49 ..
-rwxrwxrwx 1 cactiuser cactiuser 94816 May 23 17:05
corerouter_lpz_1_traffic_in_8.rrd
-rwxrwxrwx 1 cactiuser cactiuser 94816 May 23 17:05
corerouter_lpz_1_traffic_in_9.rrd
-rwxrwxrwx 1 cactiuser cactiuser 94816 May 23 17:40
core_router_lpz_traffic_in_10.rrd
-rwxrwxrwx 1 cactiuser cactiuser 94816 May 23 17:40
core_router_lpz_traffic_in_11.rrd
-rwxrwxrwx 1 cactiuser cactiuser 94816 May 23 17:40
core_router_lpz_traffic_in_12.rrd
-rwxrwxrwx 1 cactiuser cactiuser 94816 May 23 17:40
core_router_lpz_traffic_in_13.rrd
-rwxrwxrwx 1 cactiuser cactiuser 141640 May 23 17:05
localhost_load_1min_5.rrd
-rwxrwxrwx 1 cactiuser cactiuser 47992 May 23 17:05
localhost_mem_buffers_3.rrd
-rwxrwxrwx 1 cactiuser cactiuser 47992 May 23 17:05
localhost_mem_swap_4.rrd
-rwxrwxrwx 1 cactiuser cactiuser 47992 May 23 17:05
localhost_proc_7.rrd
-rwxrwxrwx 1 cactiuser cactiuser 47992 May 23 17:05
localhost_users_6.rrd
-rwxrwxrwx 1 cactiuser cactiuser 0 Jan 3 23:08 .placeholder



Whan can the problem be?.