When I run a Django project in debug mode with Eclipse (and PyDev plugin) it stops in all the breakpoints correctly and I can inspect all the values of the environment variables, but when I try to write whatever in the console I get this error and it doesn't print anything else:
[Invalid Frame]: Please select frame to connect the console.
Humm, turns out this was a bug when debugging multiple processes in PyDev. I just fixed it in https://github.com/fabioz/Pydev/commit/e13fd81fe87365be54aed8405741f84df90f2fca.
It should be released on PyDev 4.5.0. In the meanwhile, as a workaround to have a console with such a connection you can right-click the stack (in the debug view) and select PyDev > Debug Console -- by doing so, you'll have an interactive console with a proper connection to that frame.