Canon P-150 Scanner on iMac OS X (10.7.3)

Canon P-150 Scanner on iMac OS X (10.7.3)

I bought a Canon P-150M scanner for my iMac. After several attempts at downloading and installing the relevant driver for OS X 10.7 I am still unable to use the scanner. The CaptureOnTouch softaware is installed but the P-150M isn't recognized. On the P-150 the blue light is on, but the CaptureOnTouch software refuses to acknowledge its presence.

The CaptureOnTouch software launches both from the Launchpad and the Menu bar. However, once launched the Start button quickly changes from green to grey - indicating that the P-150 cannot be used.

Anybody have any suggestions?

PS The same Canon scanner works on the old Windows system without a hitch and is quite impressive in the quality and speed.