How can I download an ipod touch app from the internet and install it?

There is an app called agileforces that you could only get on a jailbroken ipod touch or iphone with 1.1.5 firmware or below I had it on my old itouch 1st gen but i traded it for a 2nd gen. I downloaded the app from the internet and ssh'd into my itouch and put it in the app folder and when i open it from my itouch it opens and then it crashes. what am i doing wrong. 10 points to best answer.