ibook g4 system updates fail?

My updates fail for my ibook g4, help please!

im new to macs so i dont know much about the operating system and my laptop is old and was not updated since july of '06. Now when i try to update the system it finds the updates but when i click install it says "all updates failed" after a few seconds. it also says for me to check if i am authorized to install caches which im not really sure what it means by that.
also i wanted to ask what a keychain password is and how i can make a new one or reset it.

it also will not let me download anything of safari=( its mac OS X 10.3.9

OK big help when posting if you mention the OS you are using. Things have changed as they have upgraded the OS, but on the assumption you are on Panther then try and download a copy of this and install it.
It is probably asking for the Admin password to allow the update - if it specifically mentions Keychain then chances are the admin password has been changed but not the Keychain - normally same password does for both.
Do you still have the original install disks - you can use them to change the password/s.