I got the following problem
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more
Running in Debug Mode
When you're developing and debugging an application, you will typically run with the debug attribute in the web.config file set to true and your DLLs compiled in debug mode. However, before you deploy your application to test or to production, you should compile your components in release mode and set the debug attribute to false.
ASP.NET works differently on many levels when running in debug mode. In fact, when you are running in debug mode, the GC will allow your objects to remain alive longer (until the end of the scope) so you will always see higher memory usage when running in debug mode.
Another often unrealized side-effect of running in debug mode is that client scripts served via the webresource.axd and scriptresource.axd handlers will not be cached. That means that each client request will have to download any scripts (such as ASP.NET AJAX scripts) instead of taking advantage of client-side caching. This can lead to a substantial performance hit.
Source: http://blogs.iis.net/webtopics/archive/2009/05/22/troubleshooting-system-outofmemoryexceptions-in-asp-net.aspx