My PowerMac G5 uses a USB Bluetooth adapter, and it kept telling me to replace the batteries in my Mighty Mouse. On one occasion I solved it by unplugging the USB adapter, but this didn't work on the second occasion, but moving the adapter to a port on the G5 worked. These warnings showed up when booting from the leopard DVD.
same here.....I replaced batteries etc but the installer still couldnt see the mouse. Pressing some random keys on my keyboard got me to the next screen where my mouse was recognized.
I also have a wired keyboard and a wireless mouse and recently installed the Leopard operating system. Shortly after installing the update the wireless mouse stopped working. seems that the iMAC bluetooth no longer recognized the wireless mouse. In order for the iMAC to recognize the mouse again I had to shut down the iMAC by pressing the on/off button and restarting. This happened four times so far. Customer support was friendly but it required about 45 minutes of waiting to get to the right support section. Finally, the only thing that was offered was to re-install leopard and archive. The next step would be to un-install Leopard and go back to TIGER. In short, in answering your question, Yes ... there is an issue with installing Leopard on iMAC when a wireless mouse is used.