Hi Dennis,
Browsers are very forgiving when it comes to invalid markup. So, although </form></form> is incorrect from a standard's perspective (you either have one </form> too many, or you tried to nest forms which is not allowed), the browser will happily display it.
You can use an on-line code validator (or Dreamweaver's internal validator which is not as good as the on-line version) to check your code.
http://validator.w3.org/
Regarding the InstanceEndEditable: in a browser these are seen as comments. This means you can have as many as you want, or none at all, from the browser's perspective.
However, Dreamweaver uses this for its template structure. It's quite picky about them so you'll find that if you have too many of them, or remove one of them, your template falls apart. In that case, reapplying the template might work.
You can use Ctrl+F to find in files. The dialog has a number of options that allows you to search in the current document, or in multiple documents / the entire site.
Hope this helps,
Imar
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Imar Spaanjaars
Everyone is unique, except for me.
Author of
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Beginning Dreamweaver MX / MX 2004
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