html5 meta validation warning

Dear W3C!

I checked my HTML5 website width only header meta elements and I've got 
so many error message, because I wrote my page these meta tags:

|<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" /*>
....
*||<meta name="DC.creator" content="My Name" /*>*
....
||<meta name="twitter:card" content="summary" /*>
....
*|

If I put Compatible, DublinCore or Twitter meta elements to my web pages 
I get the same error:
"Bad value twitter:card for attribute name on element meta: *--meta 
element name--* is not registered."

Please correct these warnings.

If you can please let me inform how to develop this problem.

Thank you,
Sándor Daragó - Hungary