zend framework invalid command 'rewriteengine'解决办法
zend framework tutorial时候，运行例子，浏览器报错为：
the server encountered an internal error and was unable to complete your request. either the server is overloaded or there was an error in a cgi script.
apache error.log 中出现如下错误：
invalid command 'rewriteengine', perhaps教程 mis-spelled or defined by a module not included in the server configuration
解决办法：
打开httpd.conf ，取消 loadmodule rewrite_module modules/mod_rewrite.so前的注释
