HTMLDOC Problem:

Htmldoc produced no pdf-output.
Commandline:

/usr/bin/htmldoc --bodyfont Arial -t pdf13  --webpage -f /www/htdocs/w0078ff5/typo3temp/hd_cu8KQr - 2>/www/htdocs/w0078ff5/typo3temp/se_AJzrnB

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.

HTMLDOC(12117) INFO: HTMLDOC 1.8.27 starting in CGI mode.
HTMLDOC(12117) INFO: TMPDIR is "(null)"
HTMLDOC(12117) ERR005: PATH_INFO is not set in the environment!
Can't open display: