I think it is really OK for anyone who think they know the answer to help, even if the answer is wrong. Wrong answers are usually flagged here by some more experienced monks replying to these answes and explaining why this is a bad solution. I think it really helps not only for the newbie who tries to participate but to the whole community as it shows what must be avoided and what mistakes you might make solving a particular problem.
Of course there are also good answers that newbies produce and this is surely very welcome
Update: After reading Abigail-II's post I must say that I partly agree with him. I think the person answering should warn that s/he is not absolutely sure about the solution. At least that is what I am doing when I am not 100% sure (or even if I am pretty sure but I can't test if it really works)