DOCBOOK: problems with imageobject

Hi,

I'm trying to generate a pdf file and get following error:

| user@host:~> db2pdf test.xml
| 
| [...]
| 
| ! LaTeX Error: Unknown graphics extension: .eps.
| 
| See the LaTeX manual or LaTeX Companion for explanation.
| Type  H <return>  for immediate help.
|  ...                                              
|                                                   
| l.351 {EPS}}
|             \endNode{}\endNode{}\endSeq{}\endPar{}\endNode{}\endNode{}\endPa...
| 
| [1.0.31[/var/lib/texmf/dvips/config/pdftex.map]] (test.aux) )

The corresponding snippet in test.xml is following:

      <screenshot>
	<mediaobject>
	  <imageobject>
	    <imagedata fileref=" figures/main.eps" format="EPS"/>
	  </imageobject>
	  <imageobject>
	    <imagedata fileref="figures/main.png" format="PNG"/>
	  </imageobject>
	</mediaobject>
      </screenshot>

Both files exist and are readable. The code works for html output
(.png). What am I doing wrong?

Best Regards,
Oliver