[TYPO3] strange permission error

[Peter Gyongyosi]

Hi all,

I'm experiencing a weird problem and I thought I might ask if any of you has ever experienced anything similar. 

When the user tries to upload an image to a standard image type content element, she gets the following error:

Errors: 
 1: Attempt to insert a record on page '[root-level]' (0) from table
'tt_content' without permissions. Or non-existing page. 

The real strange thing is that I simply cannot reproduce this error when logging in with her account: everything seems to be set up and working perfectly. We went through the steps one-by-one several times doing exactly the same thing at the same time -- she got the error, my image got uploaded. 

She's working on a remote site, so it's a bit hard to do detailed debugging: the only thing I know that she's using IE with quite strict settings, she's behind a restrictive proxy (but seems to have full access to the site) and her network connection is slow. But even if I load an IE and stricten its security settings to the point where the backend starts to be totally unusable and deliberately slow down my connection to a few k/sec and try to upload huge images -- everything's just fine.

Any ideas? :)

Greets,
Peter