[VE][50]omitted tag minimization parameter can be omitted only if OMITTAG NO is specified

I wrote a simple web page, using xhtml 1.1. It should be valid, but the
validator says me that there are many errors, but I am not able to
understand why the page is wrong: it seems be valid, and it works with all
browsers.

The web page is http.//malexprojects.ath.cx/

and this is the validator output
http://validator.w3.org/check?uri=http://malexprojects.ath.cx/&charset=(detect+automatically)&doctype=Inline&ss=1&outline=1&group=0&No200=1&verbose=1&user-agent=W3C_Validator/1.767#outlineresult


where is the issue?

Thanks for you support.