FC4 on iMac G5

[Zoltan Kota]

 I have problem with FC4 on an iMac G5.
 I could install FC4, after reboot I could/can login. But within some
 minutes of using, the system doesn't respond and I get the following
 messages on the console:

 ata1: command 0x35 timeout, stat 0x50 host_stat 0x4
 hda: lost interrupt
 mpic_enable_irq timeout
 ata1: command 0x35 timeout, stat 0x50 host_stat 0x4
 ...

Any idea what's this? Is it only for me, or it is reproducible on
other machines?
What should I try? Should I create a bugzilla entry?

Zoltan