I'm new at this and I'm having some of the same problems others have had with the side bar displaying on the bottom of the page. Since use of validator.w3.org has been suggested every time I went ahead and tried it. I found the results confusing. For example, LOTS of wordpress tags are listed as "undefined." Do I simply ignore those kinds of errors? I assume the tags are valid for wordpress even if they are not HTML or XHTML tags. Or what about errors like "end tag for "ADMINNICENAME" omitted, but OMITTAG NO was specified?" What do I do with that? I've not edited anything at all other than to create actual posts.
My blog address is at http://www.rongoodwyne.com. As with others, about half the themes I try end up with the side bar on the side. Others simply do not display comment links.
If I've omitted necessary information, please let me know and I'll supply whatever information necessary. Thanks for any help that may be forthcoming.