I am running the latest version of PDF server 1.3, with both my pdf server and a search head that is generating reports are running 4.3.1 and I'm getting the following error.
2012-04-03 09:45:29,946 INFO pdfhandler:646 - Starting PDF App Renderer Version 1.3
2012-04-03 09:45:29,946 INFO Starting PDF App Renderer Version 1.3
2012-04-03 09:48:39,290 WARNING pdfhandler:449 - Failed to query remote web server at http://splunk1:80/config/version:
2012-04-03 09:48:39,290 WARNING Failed to query remote web server at http://splunk1:80/config/version:
2012-04-03 09:48:39,290 ERROR pdfhandler:761 - (400) Remote host does not look like a Splunk server; aborting PDF generation
2012-04-03 09:48:39,290 ERROR (400) Remote host does not look like a Splunk server; aborting PDF generation
I have ensured that DNS resolution works, I have ensured that all items are properly installed for the PDF server, and yes it's on a *nix system.
What are your settings in the "email" stanza in the "alert_actions.conf" configuration file ? (config file probably lives in $SPLUNK_HOME/etc/system/local)