Sidebar Behaves Differently on Wordpress Archive Pages

Question

I am stuck on this one...

I have modified the default theme to a design my client came up with. All my modifications seem to be working okay, except the pages selected from the archive dropdown menu. Here's a link to an example page where the problem exists: http://mtrainierphotos.com/blog/?cat=15

Everywhere else the sidebar looks as it should.

Someone told me to look for a missing tag but I can't track it down.

Any suggestions?

Answer 1

I find that using the W3C Validator helps when trying to locate missing tags and may other html errors: [Invalid]Markup Validation of mtrainierphotos.com blog ?cat=15 - W3C Markup Validator. Scroll down in the validation report to see line numbers and source code.