w3 validation errors

[Chadi]

Trying to get the site as clean and 'valid' as possible according to w3 standards.

Unfortunately it is showing 89 errors now. Horrible (even though site loads instantly and displays fine). Most of them are these errors that I cannot figure out and need help on.

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Line 897, Column 67: end tag for "img" omitted, but OMITTAG NO was specified

?" src="images/yes.gif" width="16" height="16"></td> ✉
You may have neglected to close an element, or perhaps you meant to "self-close" an element, that is, ending it with "/>" instead of ">".

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Line 897, Column 2: start tag was here. <img alt="Check" src="images/yes.gif" width="16" height="16"></td>

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Line 960, Column 188: there is no attribute "allowtransparency".?" scrolling="auto" allowtransparency="yes" name="cboxmain" id="cboxmain" stylLine 2288, Column 105: ID "collapseimg_forumhome_activeusers" already defined.?e('forumhome_activeusers')"><img id="collapseimg_forumhome_activeusers" src="


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).

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What exactly are they saying here and HOW would I resolve this correctly?