Mac problem: Why am I losing my file extensions?

Factual Questions
1

I have a MacBook running 10.4.11. When sending someone a CD I burned, I discovered that some of the files have had their extensions (.eps, specifically) from their names. But not ALL of them. Some .eps files are fine, some are not. The thing is, all of them show the full file extension on my machine. But when I send them elsewhere, whether via burned CD or USB flash drive, the .eps doesn’t always show up. (Although if I bring them over to a different machine, rename them, and then copy them back and forth, the .eps seems to be stable.)

Any ideas what’s going on?

2

Hmm. Never mind. It seems to be that I have the Finder prefs set to “Show all file extensions”, and even though I usually insist on naming files with their extensions, I must have missed a few and it was putting in “phantom” extensions that didn’t carry through to other machines.