[Zope] problem on delete off a ZObjectManager

[dorian santner]

I have an object to delete (id=Santner.Dorian) and 
try to call a method (EPerson_delete) that is defined in the ZClass (EPerson)
which simply does:

<dtml-call "manage_delObjects(id)">
<dtml-if DestinationURL>
 <dtml-call "RESPONSE.redirect(DestinationURL+'/index_html')">
<dtml-else>
    <dtml-call "RESPONSE.redirect(URL1+'/index_html')">
</dtml-if>

So I call http://myDomain/Test/Santner.Dorian/EPerson_delete

>Error Type: BadRequest
>Error Value: Santner.Dorian does not exist

but it exists!
Looks like Zope doesnot find the Santner.Dorian Object

Funny is, that the upper method works with a simple ZClass,
but does not, if the BaseClass is an ZObjectManager !

the ZClass - which does not work - extends  the BaseClass ZObjectManager. So it has BaseClasses : 
ZObject, CatalogAwareBase, ZObjectManager (and it has several other Objects in it)

while the other ZClass (where the upper method works fine ) only has: 
ZObject, CatalogAwareBase 


how to delete an ZObjectManager ?