Is it safe to rename my HD volume after I am done with the installation?

I heard that when installing Leopard, it is always safe to name it one word.

I renamed my volume 2 words, "Macintosh HD" after the installation, or else if I did during the installation, my Hard Disk would not boot, and instead will stay at a blinking cursor before booting.

Is it safe what I did even though I changed the info after the installation?

Why am I unable to boot from a HD Volume that is named with two words instead of one?
Why does if I change it after the installation?


Lets me know, thanks. =) Trying to get this dispute out of my mind.