Disk Utility & Leopard - Errors?

I've noticed now on two different machines errors in Disk Utility (when loaded from the Mac OS X Installer DVD) when I try to either erase or zero the disk. I've seen three different error messages depending on the order of events:

- Zero disk failed
- Resource busy
- Unable to open disk

I've seen these problems on both the 10.5.0 and 10.5.1 DVDs. Never noticed this problem in 10.4.x.

The only "solution" I've seen so far has been to quit Disk Utility and then re-launch it.

Anyone else experiencing this? Is this a known/documented error? Any info would be great.

-Keith