application conflict

Trying to install a Lide 210 scanner on my iMac (OSX 10.6.8). Comes up with a nonsence error message (release unlock button - which I have done). First reaction was faulty hardware (as per Canon guidelines if this happens) so I got a replacement - same problem so assumed they had a faulty batch. Purchased from another outlet and same problem. Then occured to me (duh) to try attaching to my laptop and it works fine on there - just my iMac. Spoke to Canon support and came to the conclusion that there was an application conflict. So... where to now? What's the best way of going about isolating an application conflict? Is there any software I can use to help me out?