Updating from 9.0.4 to 9.1 - Error!

Question

So I have a Summer 2000 iMac G3, 500 MHZ, upgraded to 384 MB RAM. Wiped the whole HD, clean install of original OS9 disk. I want to upgrade to 9.1, so I downloaded the file from Apple. I see "Mac OS 9.1 Update.smi" on my desktop. When I go to open it, I get a red error box that says:
The application program "Mac OS 9.1
Update.smi" could not be opened,because
an error of type -39 occurred.
I have deleted and redownloaded several times, but no dice. Somebody want to help me out?

Answer 1

If the download file is probably just what it says, as an 'update' that usually means
the previous full OS 9 version would have to be installed first and running the Mac.
OS 9.1 is far superior to OS 9.0, and should be installed from a retail CD; for access
to the correct Disk Tools and other complete installation parts only found on that disc.
And OS 9.2.1 is overall a much better system for G3 Macs, than OS 9.1. {A download
update for 9.2.1 - to 9.2.2 gives it the file step. OS 9.2.1 is available as retail CD install.}
The CD was the main path to upgrade from Mac OS 8.6, 9.0, 9.1, 9.2. major steps.
Some older files have been made available online to update older OS systems.
You may have to re-install the iMac's OS 9.0 and then see if this update file works.
Or open the download file and turn it into a disc image; such as a CD would have.
Be on the lookout for two 512MB RAM sticks for that computer, and OS 9.2.1 CD.
And be sure before tempting the G3 iMac with any OS X install disc, you have the
correct Firmware Update installed in the computer, while it is running OS 9.1/9.2.
Hopefully you can make the transition update file work.
Good luck & happy computing!