<customErrors mode="Off"/> Runtime error

[upcomingaman]

I have a web application It works well in my local folder.. When i upload
it
to my web server i got

To enable the details of this specific error message to be viewable on
remote machines, please create a <customErrors> tag within a "web.config"
configuration file located in the root directory of the current web
application. This <customErrors> tag should then have its "mode" attribute
set to "Off".




Server Error in '/' Application.
--------------------------------------------------------------------------------

Runtime Error
Description: An application error occurred on the server. The current custom
error settings for this application prevent the details of the application
error from being viewed remotely (for security reasons). It could, however,
be viewed by browsers running on the local server machine.

Details: To enable the details of this specific error message to be viewable
on remote machines, please create a <customErrors> tag within a "web.config"
configuration file located in the root directory of the current web
application. This <customErrors> tag should then have its "mode" attribute
set to "Off".



I had also uploaded 2 extra files "new.html" and "new.jpg".If I type these filename in url i.e www.xxxxx.com/new.jpg OR www.xxxxx.com/new.html then these two files are accessible but if type any of the .aspx file which is present in my Project then it shows the above error

  <system.web>
        <customErrors mode="Off"/>
    </system.web>

this line i had already added in web config file but still nothing has changed.

Please Help Me to overcome this problem