If a program that uses ISWizard to install requires a
registration number, you can bypass installation AND the
regkey with this.
It's a dos program.  Run it on the data.z (or whatever.z)
like this:
C:>ICOMP -D -I DATA.Z
The -d switch decompresses, and the -i switch creates
subdirectories.

I used this with Macopen, and I realized that I was never
asked for a key (which I had) because I manually installed
it.
Obviously, Installshield doesn't publicize this decompressor
for their compression scheme.
Enjoy!