Site Not Validating – One Error

I’ve been working for hours to get my site to validate, and I’ve managed to get it down to one error, but I can’t figure out where the error is, or exactly what it is. Here’s the error I get:

Error Line 227 column 3: document type does not allow element “li” here; missing one of “ul”, “ol”, “menu”, “dir” start-tag.

• The mentioned element is not allowed to appear in the context in which you’ve placed it; the other mentioned elements are the only ones that are both allowed there and can contain the element mentioned. This might mean that you need a containing element, or possibly that you’ve forgotten to close a previous element.

  One possible cause for this message is that you have attempted to put a block-level element (such as “” or “<table>”) inside an inline element (such as ““, “<span>”, or “<font>”).
  

I’ve looked all over for extra tags and missing tags, and I can’t find anything. I would appreciate any help. Thanks!