CS1595 '...' is defined in multiple places error when you use a user control

CS1595: '_ASP.FormsLoginPart_ascx' is defined in multiple places; using definition from 'c:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\Temporary ASP.NET Files\recruitment_selfservice\858213b9\9a24bb64\tyrklreb.dll'

I have this error often, because some .net webcontrols have the same file name, though they belong to different namespaces. I googled this a little bit and there are a few solutions.

The idea is from velocity reviews thread