want to see actual error message in SharePoint Site

If you are a developer you would need to see proper error message in SharePoint site. So open your web.config file. Now set <customErrors mode=”On” /> to mode=”Off”. [ Check < SafeMode … CallStack=”true”> , compile=”true” and debug=”true” to enable Visual Studio (2010 beta) debugging .]

Perfect. Now you should be able to see exact error message.

Hope this will help.