Well, my guess is that when you put in
-background=>"/data/images/night.jpg"
it'll work fine. This is because the
client side (the browser) doesn't know
about you remote side paths. It will ask for
'../data/im..' while if you ask your http
server, the image is located at '/data/im..'.
Check your webserver's documentation for more info

I can't help you with the software error, as I
can't see what's line 30, and you didn't give us
the full error message. You should check your
webserver's log and paste all the output regarding
your script. Putting use warnings; above
your script will also make your script more verbose.