trying to upgrade my wifes mac g3 from OS 9.0 too OS 9.1 keep getting a message that says " this program cannot run on your computer see documentation for more infomation" im useing an upgrade disk and have a full version of OS 9.o on it now what am i doing wrong??

It may be that your 9.1 CD isn't made for whatever Mac you're trying to install it on, or you have to update some Firmware first.

If you already have OS 9.0 installed on the Mac, I'd suggest using the upgrade path detailed HERE, and download the installers listed there as well.

Please note, you HAVE to update 9.0.x -> 9.1 -> 9.2 -> 9.2.1. You cannot skip directly from 9.0.x to 9.2.1 using these updaters. Also, you should boot without extensions (hold down shift at boot) before installing these updates.