Plugin: SimpleFlickr – error invalid frob

I’m trying to install the plugin ‘SimpleFlickr’ by Josh Gerdes on a friends blog. I already use it on my own WP-blog (www.kenley.dk) where it works superfine.

I was therefore pretty surprised to receive an error-message when trying to install it on this new blog.

I get through the authentication part alright (on Flickr it cool). But once I push the GetToken-button in WP, I get a red box at the top of the page saying: “Error – Invalid Frob”.

Now what does that mean.. And how do I solve it and make the plugin work?

Yours Ken