Re: location of logs or pidgin and firefox
I'd rather recommend to start them from console so that you can see in real time possible errors printed out in the console.
The folders in which the logs are kept for pidgin is /home/USERNAME/.purple/ and for firefox /home/USERNAME/.mozilla/firefox
Not sure however if you would find logs for the crashes as well
~ There are 10 types of people. Those who understand binary, and those who don't. ~