# Error Line 98 column 228: ID "HomeCenter" already defined.
...th="244" height="300" border="0" id="HomeCenter" /></div></td>
An "id" is a unique identifier. Each time this attribute is used in a document it must have a different value. If you are using this attribute as a hook for style sheets it may be more appropriate to use classes (which group elements) than id (which are used to identify exactly one element).
# Info Line 53 column 249: ID "HomeCenter" first defined here.
...th="287" height="300" border="0" id="HomeCenter" /></div></td>
# Error Line 254 column 8: end tag for element "li" which is not open.
The Validator found an end tag for the above element, but that element is not currently open. This is often caused by a leftover end tag from an element that was removed during editing, or by an implicitly closed element (if you have an error related to an element being used where it is not allowed, this is almost certainly the case). In the latter case this error will disappear as soon as you fix the original problem.
If this error occured in a script section of your document, you should probably read this FAQ entry