I think you may be right, possibly we do not have a subscription to the materials on the IEEE site.
If you can use other Athens authenticated resources, such as the databases on the library eresources from home, then your Athens account will be working. If not, you need to install the permanent Athens cookie (see http://www.newman.ac.uk/library/AthensDA.htm#pickupcookie)
For help on the specific items you are trying access I would contact the liaison librarians on email@example.com or phone them at 0121-476 1181 ext. 2413.
Hope this helps,
Systems Librarian (firstname.lastname@example.org) ext 1526