Pb with interfaces => result are false

[gaylord]

First sorry for my english i'm french and i speak not very well

I've installed cacti on a Debian Sarge in order to monitore a lot of thing like Win 2K server (cpu hard disk space ram traffic ), router and switchsµ.
But i've a problem: the traffic show in graphs for router (Cisco and Bintec) is really small and doesn't correspond to the reality a contrary to result of 2K server interfaces which works well

If someone can give me an idea ...

Thanks

[gaylord]

If you can't understand my english please say it

Thanks