Fixed
Thanks to Google + Internet, and then MacFixItForums and Appletechs for the answer. In case anyone else has this problem, and happens to find this post through a search. The problem may be corrupt data in your Mac's PRAM. Flash the Mac PRAM by retarting while holding the keys :
COMMAND(Apple Key) + OPTION + P + R
upon restarting your Mac. You will see a flash/flicker of the screen before the Mac logo appears, and then the the Startup Beep/Sound again, at which point you can release the keys. I downloaded the OS9.1 updater again (this may not be necessary) and this time no checksum nor Installation Tome Error. The Update ran perfect.
Although I have not tried this, apparently you can "deep reset" the NVRAM and PRAM by using OPEN FIRMWARE upon restart with the keystroke combo:
COMMAND + OPTION + O + F
and then issuing a:
#1) reset-nvram
-then-
#2) reset-all
The site says dont screw around issuing random OPEN FIRMEWARE commands if you don't know what you are doing, or you may F up your hardware. The above two (2) commands are supposed to be safe but other than that exercise caution.
See the following links:
Free Software Downloads and Reviews for Windows, Android, Mac, and iOS – CNET Download
-and-
tp://www.appletechs.com/archives/00000043.html (outdated link removed)
Good Luck
