error flashplaceholder

I am trying to use flashplaceholder control but when i put it in the aspx
it 
give me an error:

Error when creating the control The type 
flashPlacehoder.FlashPlaceholderControl of the assembled one cannot be
loaded 
to flashplaceholder, Version = 1.0.2292.17731, Culture=neutral, 
PublickeyToken=null

I create a customcontrol and i add it to the CMS tools.

Thanks