[Zope] Problems in file upload

[Nello Polesello]

Good morning,
anyone ever had problems with the standard template file_edit_form "Add new 
element" - "File"?

With some files (pdf) I obtain "Document contains no data" with Firefox, 
while Explorer gives me a blank page.

I discovered it does NOT depends on file size (I uploaded without any 
problems a 5 MB file and I can't upload one of 1.6 MB).
I never saw this problem on other sites I created with Plone, but only in 
this server.

Nello.