[Zope-CMF] Error creating Folders - possible bug?

[mcolli@SyscomCipher.com.ar]

Hi,

I have a web site created in Plone (Zope 2.5.1, Plone 0.9.9) and when I try
to create a Folder through it I receive a message: Please correct the
indicated errors.

But really there is no error to correct , so if I go to Folder Contents,  I
can add documents in that folder created and then rename the id...from
Folder.2002-08-20.0719, for example, to a more familiar name.

How can I do to avoid this kind of messages as they are rather confusing
for the users...

Is this a known bug?

Thanks and regards
Mariela