HTMLDOC Problem:

Htmldoc produced no pdf-output.
Commandline:

/usr/bin/htmldoc -t pdf13  --webpage -f /var/www/vhosts/zirkustraeume.de/httpdocs/kinder/typo3temp/hd_lZ2LT1 - 2>/var/www/vhosts/zirkustraeume.de/httpdocs/kinder/typo3temp/se_xZQb9b

safe_mode is turned on!

This is the (stderr) output of the htmldoc command without the htmldoc_append parameters:
If you see no errors here please check your htmldoc_append parameters too.