[TYPO3-english] Cannot log in to backend

[Lamb, Brian]

Hi all, 

My website was recently upgraded to typo3 4.7.0 (from 4.6 something) and I cannot login to the backend. I tried going to /typo3/install and going in that way but it won't let me login that way either. I verified that the hash key generated from that password matches what's in the localconf.php file. 

So why am I all of a sudden unable to login?

On the front end, I'm also getting this error:
Fatal error: require_once() [function.require]: Failed opening required '/t3lib/class.t3lib_htmlmail.php' (include_path='/contrib/pear/:.:/opt/software/php/lib/php') in /typo3conf/ext/tt_news/pi/class.tx_ttnews.php on line 44

Thanks, 

Brian Lamb