I am trying to add a webpart from the webpart gallery
and this is the error I am getting.

"A Web Part or Web Form Control on this Web Part Page cannot be
displayed or imported because it is not registered on this site as
safe."

Any suggestions as to how I can go about registering them as safe and
removing this error? I do know it has to be changed in the web.config
file under wwwroot. Thanks in advance.