Failing installer
Application installation craps out, a mystery is created and then solved.
Symptoms
Following the purchase of a new computer and a new hard-drive for an old computer, the installer for a much-loved game (Ticket to Ride) would choke half-way through with a repeated series of "could not write" error messages for various components of the app. This happened on both machines, despite the fact that it had previously been installed on one, and that the OS version and selection of extensions hadn't changed.
Diagnosis
The CD was unmarked and apparently uncorrupt. Dragging the installer to a disk and running it from there ended with the exact same problem. Interestingly, just before this trouble, I had also had problems with other applications that were installed by simply dragging into the 'Applications' folder. OSX would report that I did not have permission and had to authenticate with my root password.
Solution
I ran 'Disk Utility' and repaired permissions on both disks. Something that I had installed on both systems had changed the permissions subtly on the 'Applications' folder so that installers would fail as they didn't have root access. (Later experience shows that several Java installers appear to be the culprits.) Fixing permissions solved this. Just why OSX is so vulnerable to corrupt permissions is a mystery. The OS comes with an application to repair them. Isn't there a better solution?
Technical details
Machine: MacBook and iMac flat; OS version: 10.4.7; App version: 1.0.7;