Slic3er throws "AMF parsing requires XML::SAX"
The slic3r software is written in Perl, a programming language that can be expanded with local libraries.  XML::SAX is one such library.  CPAN is a tool which can be used to retrieve libraries from the CPAN repository (Comprehensive Perl Archive Network, I believe).

I use CPAN is something I do infrequently, so I would be doing a disservice by trying to list the steps here.  Better answers are, no doubt, on stackexchange.  Nevertheless, these may help:

From your command line, start Perl running the CPAN module, and invoke the CPAN shell (your input in bold):

&gt; perl -MCPAN -e shell
cpan> install XML::SAX
cpan> ... several lines of output ...
Done!
XML::SAX is up to date (0.99).
cpan> quit
&gt;

With that done, try using slic3r again.