Error 500 : Impossible load type 'CKFinder.Connector.Connect

I've tried to integrate ckfinder in FCKEditor but I've got this problem loading CKFInder.

I've got this error message :
'Server response : 500'
'Impossible to load type 'CKFinder.Connector.Connector'

I put the CKFinder.dll in the bin directory of my web application.
But it doesn't work.

So can someone help me please ?
Thanks in advance
Cheers