Although this is a valuable resource you've posted, it didn't solve my problem.
I tried what you've said: I tried to unmount the partition (It's a 10 GB partition containing the Mac OS X 10.6 Install DVD) before I powered off my Mac and hen I logged back in, bam, there it was, the window asking me to install. I tried to unmount the whole disk, and still, bam, it's there when I logged on.
I tried what's discussed in the article, and nothing. The terminal doesn't show anything, and there's no login item directly connected to that partition / image / disk.
I tried in my MacBook and in my Mac. Nothing.
It's when I login that appears: The HD is connected to my Mac and it has one (of 8~) partitions that is an image. That image is the Mac OS X Install DVD, and the window that has the "Install Mac OS X" item ALWAYS appears when I log in. It's really uncomfortable.
Any other thoughts? Thanks for the info, BTW, I can have that in mind for the future!