Segmentation fault: METIS_WPartGraphRecursive

Dear all,
I'm complete newbie and this is the first time I use Metis. Since one week i'm trying to run this simple code but I get always a segmentation fault (core dump).
I know, i'm doing something wrong but I can't find it.

What's wrong in this code? (the graph corresponds with the example of the manual, page 18)

int n=15;
idxtype xadj[16]={0, 2, 5, 8, 11, 13, 16, 20, 24, 28, 31, 33, 36, 39, 42, 44};
idxtype adjncy[44]={1, 5, 0, 2, 6, 1, 3, 7, 2, 4, 8, 3, 9, 0, 6, 10, 1, 5, 7, 11, 2, 6, 8, 12, 3, 7, 9, 13, 4, 8, 14, 5, 11, 6, 10, 12, 7, 11, 13, 8, 12, 14, 9, 13};
idxtype *vwgt=NULL;
idxtype *adjwgt=NULL;
int parts=5;
float tpwgts[5]={0.2, 0.5, 0.1, 0.1, 0.1};
int options[5]={0, 0, 0, 0, 0};
int edgecut;
idxtype part[5];

METIS_WPartGraphRecursive (&n, xadj, adjncy, NULL, NULL, 0, 0, &parts, tpwgts, options, &edgecut, part);

Thank you very much and apologies for my possible silly question...
Best regards,