The error you're seeing ("Premature end of script headers"), is the web server's way of telling the browser that the script terminated without sending the appropriate HTTP response headers. You have code to send a response header, but it's commented out.   #print "Content-type: image/gif\n\n"; The web server doesn't get see a Content-type header from the script, and passes along the error that you're seeing. There might be a problem finding Image::Magick, or there might not. You won't know without further exploration.

Since you appear to be new to CGIs, let me suggest a two-step debugging process that will start to give you some experience and confidence. First, try the simple script

  #!/usr/bin/perl
  print "Content-type: text/plain\n\n";
  print "It works!\n";
[download]

Assuming this works, try

  #!/usr/bin/perl
  use Image::Magick;
  print "Content-type: text/plain\n\n";
  print "It still works!\n";
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If this fails, your ISP hasn't installed Image::Magick. If it works, however, you're on your way. Uncomment the lines in your script and try again.

Your server's error logs, if you have access to them, might also provide some useful information.