No, it's not compatible with Tiger. Some clues that would help you notice this:
1. The boot process has been completely revamped in Tiger, as you can see if you read
this page and scroll down to the part about launchd.
2. All previous versions of BootCD have needed an update when a new major version of Mac OS X came out. The 10.1.x version of BootCD only worked with 10.1.x, the 10.2.x version only worked with 10.2.x, and the 10.3.x version only worked with 10.3.x.
3. If you actually try to launch BootCD under Tiger, it pops up a dialog box that lets you know that it's probably not gonna work.
4. It says so in bold print
right on my web site.
Sorry, I'm just getting a bit tired of answering this question via e-mail!