help for an aircrack-ng suite user

Ok, so I've been trying to crack some wi-fi passwords using aircrack-ng. I am able to locate the .cap/ .ivs file(s) and have aircrack try to crack them, but when it asks me for a dictionary to crack with, i give it the location looking something like this: /home/user name here/Documents/password.lst. it returns by saying something like:

opening: / blahblahblah

error opening:  /blahblahblah

is not a <.pcap/ .ivs> file

depending on what order i have the captured packets/ dictionary lists in, it opens the .cap and .ivs files fine, but opening the list gives me the above error.

what form does the dictionary list have to be in? Do I have the usage messed up somewhere?

I am running Ubuntu 11.1. 

ps.  I heard that i can run airodump-ng and aircrack-ng at the same time and aircrack-ng would auto update every 5000 iv's or so. if this is true, how do i get it to auto update the packet file and read it automaticaly without me having to constantly quit aircrack-ng and then re-run it through the terminal? also, how would i go about reducing the default number of captured iv's before it auto updates aircrack?  I know this is a lot, but I appreciate anyone's time answering these questions and am sure other people would love to know as well. thank you.