Fatal error: Call to undefined function apc_fetch()

I use Cento 6 with Cpanel, PHP 5.5.24, and MySql 14.14. I installed the APC module through module installer, PECL; and then using Easy Apache compiled Apache with POD, and POD_Mysql on. But I got an error message saying

Fatal error: Call to undefined function apc_fetch() in sites/all/modules/apc/drupal_apc_cache.inc on line 131

I noticed that APC has many settings, but I only see around 6 one in PHP.ini ( Cpanel seems has put APC settings in its php.ini file). My settings on APC in php.ini are:

apc.ttl=0
apc.stat=0
apc.shm_size=96M
apc.cache_by_default=1
apc.filters="+public_html"
apc.mmap_file_mask=/tmp/apc.XXXXXX
apc.enable_cli=0

Also it seems the APC settings in php.ini has no extension= Sqlite.so, but it dose have extension=pdo_sqlite.so, no sure whether this is the cause of issue.