[Ntop] Error when start ntop

[son nguyen minh]

I have installed ntop 3.1 in Centos 5.2 by source code.
I have installed successfully and the was no error in compile progess. But when I start it. There was an error report that 
"Error Opening file ./GeoLiteCity.dat." and ntop start but I can't use GeoIP in ntop. 
Can you give me any idea. 
Thanks
Nguyen Minh Son - Dai hoc Bach Khoa Ha Noi 
Email : nmson224 at yahoo.com 
Phone : 0916016046