Fatal error: Call to undefined function rdf_db_create_repository()

To solve this issue you have to first enable RDF module, and only then the FF* modules.

FF is using RDF function to create a repository on the install, but if you install both RDF and FF at the same time, FF gets installed before RDF and therefore cannot find that function yet.

I'd be interested in good practices on how to avoid this problem. Moving the installation to hook_enable() does not help.

Same thing happens with rdf_db_delete_repository() btw if used in hook_uninstall()

It is a core problem and I don't know that there's much we can do about it.

Ideally, module weights would be defined in the .info file and Drupal would honor them when installing/uninstalling.

Of course, we *could* define new hooks like hook_rdf_install() and hook_rdf_uninstall() which File Framework would implement. Alternatively, File Framework's installation code could try to manually load up rdf.module and rdf.api.inc in the installation hooks - not perfect, but it might help some.

Arto has committed and explicit load of the rdf schema when the rdf module is not yet loaded, and fileframework now includes rdf.db.inc file before creating the repository.

Dev (cvs) releases should be used for both modules.