Web site structure question (newbie)

I have a problem that Google is not indexing my forum website very dilligently (and Yes, I have been patient!)
I think the problem MAY be the folder structure of the web site and would like some advice, please.
My web site Home folder is essentially empty, having only the host provided initial files and a google code file.
Beneath that I have my Forum folder with all the board files.
I COULD have put this at the top level but I plan, in time to have another folder at that level, say with a photo gallery and I would then tie them together with an index.html at the Home level.
Question: Is it likely that because most people come to the forum as a re-direct from the Home folder that Google is not picking up the forum?
Question: Given the ultimate structure planned, do I NEED to have the Forum down one level from the top - or would it be better to move it up there - in terms of how googel (and other BOT's) see it?