[Zope] bloody newbie: access to subfolders [from python]

[C. Koehler]

here we go for
 another stupid newbie question:

I'm trying to deal with a subfolder within a pythonscript.
I'll have to add to properties and to store a file from an upload form.
I tried it as follows---

[id shall be the name of the subfolder and is given by me]

container._.getitem(id).manage_addProperty('user',AUTHENTICATED_USER.getName(),'string')

container._.getitem(id).manage_addProperty('data',ZopeTime().strftime('%m/%d/%Y-
%I:%M%p'),'string')
container._.getitem(id).manage_addProduct['OFSP'].manage_addFile(id+'.pdf',context.REQUEST['pdf'])

by trying out this, I discovered a access proplem:
I'm logged in as admin, but the script won't work.
So: What's the problem with it?
note: everything I try with "container._.getitem(id)" fails 'cos of
access props,
but I don't know how to do it alright [I mean refering to the subfolder]

could somebody please help me [again]?
thx, Christian