Yeah, I'm kind of lost on exactly what you mean by posting "in multiple forums." If you mean across multiple sites (like here and avsim), no. If you mean posting in multiple sections of
this forum, still no.
As Jeff said, if you make a mistake and post in the incorrect section, you can always re-make the thread in another section and delete the initial post.
I'm also more than happy to move posts to appropriate sections in the forum, just send me a PM with the link to the post, and what section you want it moved to.