I found in internet one free task tracker. It is TaskFreak.
That bug tracker is easy to use and useful for small projects or small design studio.
You can get more information on official web site also you can try it (link demo)

That bug tracker use php, mysql and ajax.

of. web site | demo | Download multi user version 0.6

I like the script and i use it.

Did you forget password for your web site or account ?
You can try to use small utils. That can help you.

See in action Password Generator