Expat must be installed prior to building XML::Sablotron and I can't find #' it in the standard library directories. You can download expat from: http://sourceforge.net/projects/expat/ If expat is installed, but in a non-standard directory, then use the following options to Makefile.PL: EXPATLIBPATH=... To set the directory in which to find libexpat For example: perl Makefile.PL EXPATLIBPATH=/home/me/lib EXPATINCPATH=/home/me/include Note that if you build against a shareable library in a non-standard location you may (on some platforms) also have to set your LD_LIBRARY_PATH environment variable at run time for perl to find the library.