Internal Server Error

[d1aaa300] /matlab/api.php?action=feedcontributions&user=Mysigel&feedformat=atom MWException from line 150 of /data/klein/matlab/includes/objectcache/ObjectCache.php: CACHE_ACCEL requested but no suitable object cache is present. You may want to install APC.
Backtrace:
#0 /data/klein/matlab/includes/objectcache/ObjectCache.php(94): ObjectCache::newAccelerator(array)
#1 /data/klein/matlab/includes/objectcache/ObjectCache.php(74): ObjectCache::newFromParams(array)
#2 /data/klein/matlab/includes/objectcache/ObjectCache.php(46): ObjectCache::newFromId(integer)
#3 /data/klein/matlab/includes/GlobalFunctions.php(3935): ObjectCache::getInstance(integer)
#4 /data/klein/matlab/includes/Setup.php(579): wfGetMainCache()
#5 /data/klein/matlab/includes/WebStart.php(138): require_once(string)
#6 /data/klein/matlab/api.php(43): require(string)
#7 {main}