When I log onto the UNO library website and find the book I'm searching for, the "checking" pinwheel just spins indefinitely and nothing happens. If I try to use the "cite/export" option, nothing happens either (the window opens, but when I click on MLA format, for instance, nothing happens and it never pops open as it would if I were physically at the Criss library on one of their computers). I brought this up with the librarian in person last week, in Mrs. Wilson's class, and she thought it was odd that I would have any problems. She suggested I use this option if I encounter it again. We'll see if this works. An online tool isn't much use if it works online only when I'm physically at the library!
If you have logged in succesfully than you should have no such restrictions. You likely have an issue with a pop-up blocker on your computer. Try using a different web browser od disabling your pop-up blocker.