There are two types of Java. J2ME and J2DE. The ME ones are the mobile phone Java apps. The kind you'd find on your Symbian phone. The DE ones are desktop Java programs. The kind your browser will run with its Java plugin when you find a Java file online. MicroEmulator runs the ME ones. IcedTea (and some other app the name of which I don't remember) can run the DE ones. If it ran in MicroEmulator and it was originally something you ran on a Symbian phone, that means it's a J2ME Java program, and it won't run in IcedTea.

If the keyboard didn't work for you in MicroEmulator, well, there's not much else we can do for you - there's just some Java stuff that we can't run on our N900s in a way that's perfectly due to one bug or another.