Not sure if this problem is my 30GB iPod or a general problem?

I am a music teacher and use my iPod in school but when I keep switching to different tracks my iPod seazes up after a while which is very frustrating particularly as I work in a school for behaviour difficulties. I took it into the Apple store in Bath and they suggested downlaoding the latest software.

I have downloaded the latest software from Apple (4.7) but I can't seem to get it to transfer to my iPod!? It still registers as version 1.2 when I update??

Can anyone PLEASE help?

Thanks
Lesley