Now everything goes well.
1??Source code is displayed on the Mozilla Firefox and Google browser,because i did not config the content-type of redmine files in the conf/mime.types of apache2.2 and the httpd.conf sets 'text/plain' as default.
2??After i copy mongrel.rb including the version of rails installed, like:if ['2.3.8', '2.3.9', '2.3.10', '2.3.11', '2.3.14'] ...
to <redmine_dir>/config/initializers/, the issue "You are being redirected." (2012: Error calling Dispatcher.dispatch #<NoMethodError: undefined method `' for nil:NilClass>) is solved.