From OpenNMS

debugging information

        $opennms/share/reports/
        $opennms/logs/reports.log

make sure you have follwing packes installed

      ghostscript fonts
      xorg-x11-deprecated-libs

Check the dir

Tomcat must have write access to directory $OPENNMS_HOME/share/reports/, where OpenNMS store the PDF/HTML report before sending it via email. If not, you might see java.io.FileNotFoundException in catalina.out. So if you choose not to set the user that runs Tomcat to root, you will need to make the following changes so that the Tomcat user can read and write this directory: (assuming "tomcat4" is the group name that includes the user that runs Tomcat)

# chgrp -R tomcat4 $OPENNMS_HOME/share/reports/
# chmod -R g+w $OPENNMS_HOME/share/reports/

It should look simular to this:

reports]# ls
avail-1161619465960.fot
avail-1161632860286.fot
AVAIL-HTML-Overall-Service-Availability20061024.html
AvailReport.xml
AVAIL-SVG-Overall-Service-Availability20061023.pdf

Take note of the .fot and the AvailReport.xml and the PDF or HTML file. all of those should be there if the reports are generated properly. take a look at the PDF. if it is readable and valid ( it contains a pretty graph ) the problem will be mail related. Opennms comes with a mailer class which can be disabled.
/etc/javamail-configuration.properties

        org.opennms.core.utils.useJMTA=false
        org.opennms.core.utils.mailHost=127.0.0.1

this two option will turn off the JMTA and opennms will send mails via telnet to your mailHost.

The PDF isnt created properly, eg. it is broken.

check out the logfile The problem will be related with the pdfwriter. jar you should check the logfile and both the .xml and .fot file and see if they are valid. you can build the fot file with a tool called fop http://xmlgraphics.apache.org/fop/ fop.sh file.fot out.pdf should generate the pdf or give you an error message

Also See

http://thread.gmane.org/gmane.network.opennms.general/11974/focus=11988

http://thread.gmane.org/gmane.network.opennms.general/10056/focus=10460

http://forum.java.sun.com/thread.jspa?tstart=30&forumID=34&threadID=542044&trange=15 (when using Java 1.5)