Invalid serial number for Acrobat Pro 6.0

Question

I had to reinstall Acrobat Professional 6.0(from a downloaded copy purchased from Adobe.com). The install will not complete. It says "Invalid serial number. Please try again". The only option is to cancel, and then I get the Message: "Adobe Acrobat could not install correctly. Adobe Acrobat was unable to install a necessary component and must quit."
I have verified the number with Adobe Licensing. Adobe Support informs me that they do not support version 6 and the answer is hidden away in the knowledgebase. I have searched the forums and the knowledgebase - to no avail.
Can someone please help or point me to the Doc # (if there is one).
Please do not suggest that I download a pirated version. That is not an option for me.
G4 PowerPC 500MHZ, 1GB SDRAM, 100GB still available on HD. OS X 10.4.11
Can anyone help please?
thanks,
MWG

Answer 1

From the Knowledgebase:
> 5. Troubleshoot serial number problems.
>
> If the Acrobat installer returns the error "Invalid Serial Number"
> after you enter the serial number or during startup, do one or more
> of the following:
>
> -- Delete the serial number from the Serial Number text box, and then
> reenter it exactly as it appears on the back of the Acrobat CD case
> or in the registration guide.
>
> -- Reenter the serial number using different numeric keys. For
> example, use the numeric keys above the alpha characters instead of
> the numeric keys on the keypad.
>
> -- Make sure you typed the number zero (0) correctly, not as the
> letter O.