Unless you recompiled it yourself, Backtrack won't run on the Zaurus, as it's compiled for x86 CPUs (as opposed to the Z's ARM one).
For information on dual-booting in general, poke around in the Ubuntu/Debian sections (or search). I believe there's a thread called "multi-boot how-to" or something similar. The ZUbuntu installation thread also has a nice multiboot tutorial in it.
Hope that answers your questions.
PS- If you could break your sentences up, they'd be easier to read, likely yielding more help.