Snippet generated css file

I'm trying to use this compress CSS tutorial at http://www.cadcoder.com/index.php?id=32

I believe I've done it correctly, and when I check the output I do indeed find the compressed css file in the head. I can even open it and read it. But the page is not using those styles.

I do not however actually see the compress.css file in the filesystem where the output tells me it's located. Is there an actual .css file or not when I generate it with a snippet like this, or is it only available to the browser as a sort of ghost file?

I still do not really understand php well, if at all. I hope this question doesn't sound too stupid. I'd really like to know what I'm missing here and why this file that I can see the contents of when viewing the source doesn't want to be used or located.

Thank you,
Kori