thank you "Nestle" for your post to verifies my problem...

I've open a bug on BT5 bug tracker:

Backtrack 5 - Bug #45: etterlog doesn't extract passwords from *.eci file - Redmine

I captured a HTTP & FTP authentication and save it into a pcap file.
When I analyse this pcap file with wireshark I can see the session & credentials.

I generate a *.eci file for etterlog with...