I have a new Cisco 1812 router, which has had SDM 2.5 installed from CD. There were no errors during install. I can log in through SDM, no problem. The strange thing is that neither Configure -> Additional Tasks nor Monitor -> Logging work. If you click on either of these icons, it just stays on whichever module is currently selected. I have replicated this on 3 different machines using IE8 and Firefox 3.0.11. JAVA is version 126.96.36.199. I have reinstalled SDM, but that didn't help. I would appreciate any thoughts.
Only the following versions are supported, so it could very well be some of your pieces are too "new".