problem with iptraf tool
 

I actually installed IPTRAF on a linux machine and when i give iptraf in interactive mode i find the following error message:
Error opening IP filter data file
and iptraf also is not intercepting the ongoing traffic in the network as well.
Can someone please tell me how to overcome the error?

IPTraf cannot open the filter file. Could be caused by a shortage of file descriptors or a bad disk.

http://iptraf.seul.org/2.7/messages.html