Unable to load library, only on remote server

[eluser]Unknown[/eluser]
Hi,

I'm having a very weird error here.
I made a site in codeIgniter that displays all the pictures from a Flickr account, I used the phpFlickr library to do this. During development on my localhost, everything works perfect and all albums and pictures from Flickr are loaded.

Now i moved the site to my online webspace and now CI gives me the following error:

An Error Was Encountered
Unable to load the requested class: phpflickr

Can someone please explain me why this works perfectly on my localhost (MAMP) but not on the remote server?

Thanx
Arne