Cacti

Dear forum,
I just change my existing device which graphed in my cacti to other ip
bu suddenly my graph cannot update.

I tried to rebuild poller cached but still it's not work.
What should I do ?
my cacti version 0.8.7d

Thanks

Thanks,
i've found my problem solver on http://forums.cacti.net/about5703.html

I've looking looking on cacti how to make sum of snmp traffic on multi interface, which on mrtg so easy to do by add line :
Target[mytarget] : x:community@host1 + x:comunity@host2 + ... + x:comunity@host100

How to do it on cacti

Thanks