Deploying custom webpart to sharepoint 2010 - sharepoint-2010

Question

In sharepoint 2007 for to deploy a custom webpart i have added all of its application references as a safe control, so i got my webpart correctly. But now i using the sharepoint 2010 and need to deploy a custom webpart in it, hence i followed steps such as
1.Created a webpart(Deploy as a farm solution) using VS2010 of type sharepoint->2010.
2.Used the Sharepoint 2010 Management shell to add the webpart to the sharepoint site.
3.Then using the sharepoint Central Administrator v4->System Settings->Manage Farm Solution->Mycustomwebpart
4.Clicking on that webpart and select deploy option, and hence it is been deployed to the site.
Then in sharepoint home site ->Site Actions-> Site Settings->Site collection Features-> select Mycustomwebpart and click on the Activate button.
6.Now, for to show the webpart, i gone to a site ->site Action-> Edit Page ,then click on Add a webpart then select the custom option and select Mycustomwebpart and click on the Add button.
7.Now i getting the error as "File Not Found" with error message as Web Parts Maintenance Page: If you have permission, you can use this page to temporarily close Web Parts or remove personal settings. For more information, contact your site administrator.
8.Please guide me to overcome this error.
Lots of thanks in advance..........