[Plugin: Redirection] Undefined in the logs

Hello,
I have installed the plugin yesterday on my blog

I have some strange stuff in the 404 logs :
http://www.cloneweb.net/undefined?1239698234500
http://www.cloneweb.net/NaN?med_id=undefined
http://www.cloneweb.net/actualite/looking-for-eric-le-nouveau-ken-loach/undefined?1239698139239

What’s this undefined stuff and what can I do to remove it ?

Thanks for your help

http://wordpress.org/extend/plugins/redirection/