Each time round your inner loop you reset @rrdgraph2 to an empty list with the following two lines:

@rrdgraph1=();
@rrdgraph2=@rrdgraph1;
[download]

That may well be your problem.

I can't access the full script, but it looks to me as tho' you don't use -w or use strict. These would force you to think more carefully about the scope of your variables and would therefore help you with problems like this.

Oh, and one other thing. The line

$png= join("",$graphdir,"/",$ds,$interval,".png");
[download]

would be much easier to understand as

$png= "$graphdir/$ds$interval.png";
[download]

--
<http://www.dave.org.uk>

"Perl makes the fun jobs fun
and the boring jobs bearable" - me