Comment on Talian 5 WordPress SEO Theme by SEO Dave.
I no longer have IE6 installed, so I run the Talian theme through emulator programs and the only browser that I’ve had serious issues with is IE5.5 and as that’s really old, didn’t worry about it.
Based on your validator error it sounds like you might have something in one of your posts, a plugin or some custom code that’s throwing things off.
I get it myself from time to time when I try a new WordPress plugin and have to make minor code tweaks to make it work correctly with the theme.
You can sometimes narrow a problem down by checking the home page, multiple categories, multiple posts, multiple pages and if some work correctly and others don’t it’s probably one of your posts/pages. After that disabling plugins to rule out those.
If you’ve made custom changes to the Talian theme try uploading the unaltered theme files and see if the issue is resolved.
If you paste your URL that’s got the problem happy to take a look.