From:
http://www.suphp.org/DocumentationView.html?file=apache/CONFIG
suPHP_ConfigPath (expects a path name) This option tells mod_suphp which path to pass on to the PHP-interpreter (by setting the PHPRC environment variable). Do *NOT* refer to a file but to the directory the file resists in. E.g.: If you want to use "/path/to/server/config/php.ini", use "suPHP_ConfigPath /path/to/server/config". If you don't use this option, PHP will use its compiled in default path.
For other problem (php settings not taking affect), apache service must be restarted for chances to take affect.
Depending upon the contents of the 1.9.x backup, one might also have further tweaks to MySQL.
Check your moodledata/temp/backup folder. There may be clues therein.
'spirit of sharing', Ken