USB Webcam mistery under Ubuntu Lucid Linx

Maybe someone with better knowledge of USB can shed some light here:

I have an USB camera that I knew was working several Ubuntu versions ago. But under Karmic and Lucid it refused to work.

I knew that it was listed as supported; but after hours trying things I couldn't make it work.

Then I saw in a forum that someone said that as a final test he disconnected the USB hub and plugged in the camera directly to the computer. After that it worked, so he suspected the hub.

In my case I was connecting directly to the computer already so I thought: "I'll try the other USB port" and the camera worked!!... For a few minutes, then it stopped working.

So it occurred to me that the only difference was that when I switched ports I had disconnected the USB wireless mouse.

I unplugged the mouse and voila! The camera started working under:

gstreamer-properties
cheese
ekiga

This is, everywhere, even Skype!

One clue could be that both devices (the camera and the mouse) are Logitech so the top part of the ID is the same 046d:c50e

Bus 002 Device 006: ID 046d:c50e Logitech, Inc. MX-1000 Cordless Mouse Receiver
Bus 002 Device 003: ID 046d:0870 Logitech, Inc. QuickCam Express

What else could it be the problem here?

Later I will try with this camera in a different computer and also with different mouses.

Do you have any clues for me to investigate or provide better information when reporting the issue?