could not find triangele crash when exporting a grid

[ole]

When running \anuga_work\production\onslow_2006/test_export_results.py there is the following error;

USER: dgray
bound /d/xrd/gem/5/nhi/inundation/data/western_australia/onslow_tsunami_scenario_2006/anuga/boundaries/
meshname /d/xrd/gem/5/nhi/inundation/data/western_australia/onslow_tsunTraceback (most recent call last):
  File "test_export_results.py", line 45, in ?
    format = 'asc')
  File "/d/cit/1/dgray/inundation/anuga_core/source/anuga/shallow_water/data_manager.py", line 1945, in sww2dem
    grid_values = interp.interpolate(q, grid_points).flat
  File "/d/cit/1/dgray/inundation/anuga_core/source/anuga/fit_interpolate/interpolate.py", line 176, in interpolate
    verbose=verbose)
  File "/d/cit/1/dgray/inundation/anuga_core/source/anuga/fit_interpolate/interpolate.py", line 202, in interpolate_block
    verbose=verbose)
  File "/d/cit/1/dgray/inundation/anuga_core/source/anuga/fit_interpolate/interpolate.py", line 295, in _build_interpolation_matrix_A
    raise Exception(msg)
Exception: ('Could not find triangle for point', array([ 16375.,      0.]))

[anonymous]

Duncan - a similar error was detected running the run_building_inundation.py script in the production/onslow directory. What's interesting is that it was happy to do the calculation on onslow_P3_4.sww, but failed at onslow_P1_4.sww. This is the same sww file that export_results.py fails at (in that case, it is happy with onslow_P0_4.sww).