By path, ScooterQ means the PATH environment variable in Unix, not the path where you want the zip to be extracted to. Shells will search the PATH variable for executables and other files. If an executable isn't in one of the directories specified by PATH, then you need to use its full path (such as /usr/bin/unzip instead of unzip) to run it.

Update: Run this as a CGI script to see the what the PATH variable for CGI scripts is set to:

#!/usr/bin/perl -w

use strict;
print "Content-type: text/html\n\n", `echo \$PATH`.
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(This is untested code, but it should work unless I've made a really stupid mistake. Also, showing the PATH could be a security risk, so after you've run it, be sure to make it non-accessible by others.)