Sorry to keep adding to my own post but I'm writing as I go and hope someone can spot something I've missed along the way. The problem is directly connected to my vbulletin styles somehow. When I turn the vb3 integration option for headers, footers and styles on, I get the errors. Also, when I go under Forum Settings, using integrated forum stylesheets shows no stylesheets at all (on ReviewPosts user index page). Turning that option off forces ReviewPost to use it's own stylesheets (which I'm sure we already know).
Anyways, I hope this information can help someone help me to get everything working because beyone this, I haven't a clue. Oh, this is a fresh install of ReviewPost v4 and vbulletin 3.7. Thank you!