migration wss 3.0 to sharepoint 2010

Hi everyone,

I am working on content migration wss 3.0 to 2010 , there no custom webparts , the only we have out of box webparts.

First i run test-spcontentdatabase, i got an report on missing webparts and setupfiles 

after running the mount-spcontentdatabase ( it completes 100% with no errors), when i go and check in upgraded 2010 environment , few of webparts (eg: announcements, links) gets error.

Web Part Error: A Web Part or Web Form Control on this Page cannot be displayed or imported. The type could not be found or it is not registered as safe. 

Any help ...

thanks.

kumar