Attributes controller not working

Hi I hope someone out there can help. I recently had my zencart upgraded by a commercial outfit to 1.3.9h.

I thought I had checked all the functions were OK; but missed this - I have uploaded new products (downloadable items) and they appear on the catalogue and in filezilla but when I try to update the attributes controller it just returns to the home page. (Customers are still able to download existing products with no problems).

I have read previous threads which might be about this but they are difficult to understand. I have tried to contact the people who did the upgrade but it can only be by email and response time is very slow.

Please!