iWork tour froze iMac

Hi all,
Had this iMac for about 18 months. Decided I should (eventually) try the tour of iWork. I might like it.
When I selected said tour, I got a black and grey full screen display with a large Apple logo in the middle.
And the iMac froze!!!
Only way out was to turn off power via the power switch AND remove the power cord.
Apple machine, Apple software = frozen machine??
Doesn't make any sense to me.
Anyone seen this before?

Thanks

Neil

yes me too!

Yes I got that issue when opening iWork for the first time last week. My iMac is nearly 3 years old, running OS10.5. I also could only get my machine working by turning off the power and pulling the cord out of the wall. I emailed my local Apple dealer and all he could give me is this forum topic, no answers. Now I'm scared to even attempt to open iWork!