> It looks as if docbook DTDs for 4.1, 4.2, 4.3, 4.4, and 4.5 are all there, but
> maybe the SUSE package is missing some of the files....
Yeah, but SGML utilities also need a "catalog" which links the public
DTD identifier (the thing beginning with "-//OASIS//DTD" above) to a
filename.
They're obviously there, but they can't be found, so that would suggest
the catalog is broken.
If the catalog does not contain the right public name, then I would try
if adding it (in the correct format) fixes that. If so, file a bug with
OpenSUSE to ask them to fix their damn DocBook packages ;-)