[xml] parsing error (again)

[nico <sl1200mk2 free fr>]

hi,
i woul like to have some explanation about this error:
Thread 0 Crashed:
0   libSystem.B.dylib           0x900029c8 szone_malloc + 0xd8
1   libSystem.B.dylib           0x90000c18 malloc_zone_malloc + 0x94
2   libSystem.B.dylib           0x90001a00 malloc + 0x44
3   libxml2.2.dylib             0x808a3f58 xmlStrndup + 0x44
4   libxml2.2.dylib             0x808344bc xmlNewCharEncodingHandler + 0xcc
5   libxml2.2.dylib             0x80834668 xmlInitCharEncodingHandlers + 0x10c
6   libxml2.2.dylib             0x8084edac xmlInitParser + 0x68
7   libxml2.2.dylib             0x8084e62c xmlSAXParseFileWithData + 0x34
8   try                         0x00002eac doparse + 0x2c

because, i always got it, and i would like to use libxml2.....
i'm doing exactly the same code as shown in xpath1.c examples

this bug always appear after 1or 2 or 3 parsing....
can someone give me a point to look?
i'm running libxml2 on os x system.

thanks for any help
nicolas