Problems with Libxslt - GNOME

Hi all.
I have some doubts using Libxslt.I put the library in my server to do
some transformations.

The second execution goes well till it finds any function of libxslt.
As in my example:

{
      const char* params[1];
      xsltStylesheetPtr cur = NULL;
      xmlDocPtr doc, res;

The problems happen when xmlSubstituteEntitiesDefault(1); is called.
If I cut this line the problems will occur when
xmlLoadExtDtdDefaultValue = 1; is called. And so on.