The error message is somewhat misleading. The problem isn't with Expat.sl it is with a shared library Expat.sl uses.

chatr /opt/perl_32/lib/site_perl/5.8.7/PA-RISC1.1-thread-multi/auto/XML/Parser/Expat/Expat.sl
will show you what libraries Expat.sl depends on and where they should be located. It will also tell you if Expat.sl has SHLIB_PATH enabled. If it is enabled and the dependencies are installed in a unexpected directory then add that directory to your shells SHLIB_PATH env variables (eg export SHLIB_PATH=$SHLIB_PATH:/where/ever/the/missing/lib/is/ )