What does loaded mean?

This means exactly what it says: how busy the given programmer is at the moment.

Ok but when I am loaded it means something else.

You have to forgive Vladimir. He probably does not know the slang meaning of "loaded", being that of someone that is rich and "loaded with money" or someone that is drunk and "loaded with booze".

What counts here is that the developeres are loaded with work from the jobs they accepted.