无法在结帐页面上分配内存错误

Question

我们正在使用Opencard 1.5.6。结账时，会随机生成500内部服务器错误警报。请参阅提供的截图：

我已检查过Cpanel错误日志并注意到：

[Thu Jul 17 09:26:17 2014] [error] [client 000.000.0.000] File does not exist: /home/example/public_html/500.shtml, referer: http://www.example.com.ph/index.php?route=quickcheckout/checkout
[Thu Jul 17 09:26:17 2014] [error] [client 000.000.0.000] (12)Cannot allocate memory: couldn't create child process: /opt/suphp/sbin/suphp for /home/example/public_html/index.php, referer: http://www.example.com.ph/index.php?route=quickcheckout/checkout

.htaccess是空白的，而php.ini代码是：

magic_quotes_gpc = Off;
register_globals = Off;
default_charset = UTF-8;
memory_limit = 64M;
max_execution_time = 36000;
upload_max_filesize = 999M;
safe_mode = Off;
mysql.connect_timeout = 20;
session.use_cookies = On;
session.use_trans_sid = Off;
session.gc_maxlifetime = 172800;
allow_url_fopen = on;
;display_errors = 1;
;error_reporting = E_ALL;
default_socket_timeout =300;
extension=php_openssl.dll;
extension=php_mcrypt.dll;

任何想法如何解决这个问题？

谢谢，