Missing edge error

Hi,
I've been using Metis 4 and just downloaded Metis 5 to try out. I'm using the API calls to
METIS_PartGraphKway and METIS_PartGraphRecursive. The calls seem mostly the same as Metis 4
with a few minor changes to the argument list. Now when I try to partition using a graph,
I get the following error:

Missing edge: (23 22)!
A total of 1 errors exist in the input file. Correct them, and run again!

I get this error on a number of cases which work in Metis 4. I'm using the same graph
structure as in Metis 4 (eg, xadj and adjncy arrays) and I'm calling from a C program.
I'm using defaults for all the other inputs. Is the graph structure any different in
Metis 5?

I downloaded '5.0 Release candidate (5.0rc3)' in which the metis.h file shows
#define METIS_VER_MAJOR 5
#define METIS_VER_MINOR 0
#define METIS_VER_SUBMINOR 0