Oh my goodness!
After a million attempts on a thousand suspects, I was finally able to get to the bottom of it.
Soooooo nice! Yay!
First, no, the logs weren't much help.
Sexondly, I'm not sure what change ended up getting me past the 403, but I ended up moving on to a 500 error.
Eventually, we came around to finding that the mod_rewrite extension for apache needed to be installed.
That got us to the point where at I was at least able to access the page. (Now I'm just dealing with some php errors saying that a zend directory can't be found :-)
Thanks, m4rc3, for the attention.
Just to share, I ended up getting some great help on this particular problem at the Apache Lounge Forums