Browsing Image on Apache in rails App

Hi All,

My rails application is running on Apache server with phusion_passenger
gem. For testing purpose I used both attachment_fu and paperclip to
upload image in that application. There are two different methods, one
for image uploading using attachment_fu and another for paperclip.

When the application starts in development mode, everything works as
expected but when it comes to production mode after browsing an image
and hit upload it crashes and throws "500 Internal Server Error".

First I thought that error was occuring due to plugins but i commented
the code in both of the methods and had written a single redirect_to
line in them but still the application is throwing the same error.

Both of the plugins are working fine upto image size 7.6kb but error is
shown if image size > 7.6kb. Image validations are upto 100 kb image.

Please guide me.