Imagepng does not work: Browser says Document contains no data.

Hello folks, I got a problem with using the image functios of php. I try to create a png-Image using this few lines and it fails. Using: php-4.0.3pl1 apche_1.3.14 gd-1.8.3 I compiled gd into php, there were no errors. The apache logfile tells me that I accessed the file and he send 0 bytes back. There is no comment in apache-error log about it. Then I turned php-errorlogging on, no error during excecution of the script. The funniest thing is, that the same script works fine on another computer with exactly the same versions installed and compiled with the same parameters. Does anyone of you has an idea what else I might have missed to do ? Thanks a lot -- <?php header ("Content-type: image/png"); $im = @imagecreate (50, 100) or die ("Cannot Initialize new GD image stream"); $background_color = ImageColorAllocate ($im, 255, 255, 255); $text_color = ImageColorAllocate ($im, 233, 14, 91); imagestring ($im, 1, 5, 5, "A Simple Text String", $text_color); imagepng ($im,"/tmp/img.png"); ?> -- Gruß Paul