Hmmm, well I'm not sure how the sidebar div could end up inside the main div since I installed the code only in the plugin settings. After it goofed up, I just undid it. Some of the goofup seems to be associated with the code I installed:
<div style="color:#999999; font-size:10px; line-height:15px;">This post may contain affiliate links that allow me to receive a commission from a purchase made by clicking the link. (Thank you!) I’m disclosing this to honor the FTC’s guidelines “concerning the use of endorsements and testimonials in advertising.”
As far as the validation, I'm pretty much at a loss as to how I can fix it. I wonder if it is because I imported my posts from Blogger?