Can't locate the loadable object for module XML::LibXSLT
This simply means that the object (dll/xs.dll) that DynaLoader.pm needs to load can't be found. Assuming that site/lib/auto/XML/LibXSLT contains a file named libxslt.xs.dll (and doesn't contain a file named libxslt.dll), then it seems that DynaLoader.pm is still trying to load libxslt.dll. This would indicate that LibXSLT.pm has not been correctly modified (as per PGPLOT.pm).