Ok, so your Extras-devel repository doesn't work.

As per

http://talk.maemo.org/showthread.php?t=88707

you did not disable your previous repositories (check the first post of the above thread), since the n900 is trying to get the program from http://repository...

it should be (again, above link):

Catalogue Name: Extras-Devel - Mirror 3
Web address: http://skeiron.org/repo/repository.maemo.org/extras-devel/
Distribution: fremantle
Components: free non-free

And one more thing, be careful with extras-devel (as in development), there are programs there that can cause a lot of trouble if you are a newbie.

Good luck.