Help with Graphing

[the_ebl]

I'm new to Cacti and I was trying to run a test perl script that was just this:

open(READINGS, "c:\Inetpub\wwwroot\cacti\read.txt");

read(READINGS, $data, 4);
chomp $data;
print $data;

The text file just includes a 3-digit number with a newline character

Ok, so I ran cmd.php to see if it can open and run the script and it works. It outputs:

command: perl "c:/Inetpub/wwwroot/cacti/scripts/script.pl", output: 740

update C:\Inetpub\wwwroot\cacti/rra/light_data_13.rrd --template light_data N:740
time: 0

...etc...

So it can open the file.

When I check the graph, it does not get created...I just get a broken link. I turn on the debug option in cacti and it says:

Warning: popen(c:/Inetpub/wwwroot/rrdtool/rrdtool.exe graph - --imgformat=PNG --start=-86400 --end=-60 --title="Light Readings" --base=1024 --height=300 --width=500 --alt-autoscale-max --lower-limit=0 --vertical-label="Value" DEF:a="c\:\inetpub\wwwroot\cacti/rra/light_data_13.rrd":light_data:AVERAGE LINE2:a#0000FF:"" GPRINTLAST:"%8.2lf %s" 2>&1,r): No error in c:\inetpub\wwwroot\cacti\lib\rrd.php on line 58

Warning: fgets(): supplied argument is not a valid stream resource in c:\inetpub\wwwroot\cacti\lib\rrd.php on line 72

Can anyone help me find out what is wrong and what I can do to fix it? I get the same error when I try the random2.pl script (random number generator) in the manual...

Any help would be greatly appreciated!