I'm not sure it makes the difference but I always precede the relative path with the "file:" string like this :
<fo:external-graphic src="file:ecu.jpg"/>
That's a *bad* idea, actually violating URL syntax. See http://marc.theaimsgroup.com/?l=xml-cocoon-dev&m=102027988321347&w=2 for some explanations.
J.Pietschmann
