If missing zcat is the root of the problem, maybe you deinsalled a package which contains that?
On my system, zcat is a link to gzip, and there is a package called gzip which contains the gzip binary.
You could download that package, extract the files on another computer and then copy them to the Zaurus manually. There are only the files
/bin/gunzip
/bin/gzip
/bin/zcat (link to /bin/gzip)
in the package, so manual installation is easy.
daniel