I seem to get software corrupt when doing upgrade. Like the one below.

Why is this happening? Is there anything I can do to solve this or prevent this from happening again?

That isn't corruption -- that is just a set of bad mirrors. Remove that mirror from /etc/apt/sources.list

Thanks for the advice but how to do that. Sorry for the trouble cos I am a newbie. Only use Ubuntu 9.04 for a couple of month now and I like it except for this few annoying error messages.

Thanks. Its been awhile I have not touch the command line since the DOS days and that is MS DOS when Window 3.0 was launch. So I prefer the GUI type but I like to dabble with the command line once in a while but I am afraid I might screw up the OS when removing something. Anyway I just install Ubuntu Tweak and see how it work out.