498     $word = qw("$word") if ($word =~ /\s/);
[download]

qw does not interpolate. You probably meant to do this instead:

     $word = qq("$word") if ($word =~ /\s/);
[download]

    534     print <<ENDHELP;
    535 Hellow theres..
    536 This script (ab)uses the google image search to find an image 
+of 
    537 adequate proportions from a random word from your computers 
    538 dictionary file, and attempts to download it and set it as you
+r
    539 desktop wallpaper. If you supply words arguments, then this sc
+ript
    540 will use them as the basis of your search.
    541 
    542 Usage:
    543 random-bg.pl
    544 random-bg.pl have
    545 random-bg.pl jackie chan --delay 5
    546 random_bg.pl --rotate --delay 2
    547 
    548 If you give it words in @ARGV, it will continually show images
[download]

Arrays are interpolated in double quoted strings. You need to escape the '@' character.

    210     open(TOPIC, ">$topic_file") or die "can't open $topic_file
+";

    218     open(TOPIC, "$topic_file") or die "can't open $topic_file.
+";

    227     open(IDFILE, ">>$id_file");

    236         open(IDFILE, $id_file);

    354     open FILE, ">$file" or &debug("can't open $file\n") and re
+turn 0;
[download]

You should always verify that the file opened correctly before trying to use a possibly invalid filehandle. You should include the $! or $^E variable in the error message so you know why it failed to open.