Ciao, sto cercando di validare il mio XHTML, ho risolto tutti i problemi tranne questi

codice:
Error Line 56 column 23: an attribute value specification must be an attribute value literal unless SHORTTAG YES is specified.[*]Sponsor


Error Line 56 column 23: an attribute value specification must be an attribute value literal unless SHORTTAG YES is specified.[*]Sponsor


Error Line 51 column 46: an attribute value must be a literal unless it contains only name characters.[*]LOGO



Error Line 51 column 46: an attribute value must be a literal unless it contains only name characters.[*]LOGO
non capisco come risolvere questi problemi

Grazie