ComponentLookupError: 'Utilities' when entering /silvaroot/service_extensions/

Dear Silva developers,

I have setup a new Zope 2.8.6. instance and installed everything from
Silva-1.5.3-all.tgz archive as well as SilvaExternalSources 0.13.

When I go to http://cms:8099/silvaroot/service_extensions/ I get the 
following exception:

Traceback:
-----------------------------------------------------------------------------
Request URL 	http://cms:8099/silvatest/service_extensions/manage_editForm
Exception Type 	ComponentLookupError
Exception Value 	'Utilities'

Traceback (innermost last):

     * Module ZPublisher.Publish, line 114, in publish
     * Module ZPublisher.mapply, line 88, in mapply
     * Module ZPublisher.Publish, line 40, in call_object
     * Module Shared.DC.Scripts.Bindings, line 311, in __call__
     * Module Shared.DC.Scripts.Bindings, line 348, in _bindAndExec
     * Module Products.PageTemplates.PageTemplateFile, line 110, in _exec
     * Module Products.PTProfiler.ProfilerPatch, line 69, in 
__patched_render__
     * Module Products.PageTemplates.PageTemplate, line 104, in pt_render
       <PageTemplateFile at /silvatest/service_extensions/manage_editForm>
     * Module TAL.TALInterpreter, line 206, in __call__
     * Module TAL.TALInterpreter, line 250, in interpret
     * Module TAL.TALInterpreter, line 595, in do_insertTranslation
     * Module TAL.TALInterpreter, line 663, in translate
     * Module Products.PageTemplates.TALES, line 261, in translate
     * Module Products.Five.i18n, line 40, in translate
     * Module zope.component, line 79, in queryUtility
     * Module zope.component, line 68, in getService
     * Module zope.component.service, line 109, in getService

ComponentLookupError: 'Utilities'
-----------------------------------------------------------------------------

Any idea what's going wrong there?


Regards,
   Nico