First off, weinre doesn't have JavaScript debugging that people usually want, like break points, stepping through lines of JavaScript, etc. You can execute JS from the console, but that's about it.
I assume this is Android?
The weinre code in the target (your emulator) needs to be able to connect to the weinre server. I don't remember the ins-and-outs of Android networking for the emulator, but I think you will need to point the target to your ip address of the machine running the weinre server. And of course, you need to be able to route to that address from your emulator. You can't use localhost, I assume, because the Android emulator is running in a vm with it's own localhost.