Web.config error on server

Question

hi.
i am using VS2010 and i developed a website, i runs good on local server but when i uploaded the site on web server it gives the following error

The requested page cannot be accessed because the related configuration data for the page is invalid.

Config Source 73: <handlers> 74: <add name="CrystalImageHandler.aspx_GET" verb="GET" path="CrystalImageHandler.aspx" type="CrystalDecisions.Web.CrystalImageHandler, CrystalDecisions.Web, Version=13.0.2000.0, Culture=neutral, PublicKeyToken=692fbea5521e1304" preCondition="integratedMode"/> 75: <add name="ReportViewerWebControlHandler" preCondition="integratedMode" verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForm


when i comment these lines then again an error .

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".

<!-- Web.Config Configuration File --> <configuration> <system.web> <customErrors mode="Off"/> </system.web> </configuration>

then i set customErrors mode="Off".
after this again an error comes,

It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level.  This error can be caused by a virtual directory not being configured as an application in IIS.

Source Error:

Line 42: </buildProviders> Line 43: </compilation> Line 44: <authentication mode="Forms"> Line 45: <forms loginUrl="~/Account/Login.aspx" timeout="2880"/> Line 46: </authentication>

Can any body help me??
and one more thing i have a website running and i uploaded my site on that server by creating a folder in it.
Existing site was created in framwork 3.5 then we changed it into 4.0. and my new site is in 4.0