SelectByPolygon error : Out of stack space

Hi all !

My VBA macro breaks with a "Runtime Error 38 : Out of stack space"
error when trying to use the SelectByPolygon method.
The macro works fine but on this drawing, on of the polygons used
for selection is very complex : >30.000 vertices !

The selection is done in a loop :

For Each oAcadLWPoly In oSelSet
varArray = XYZCoordinates(oAcadLWPoly.Coordinates)
oSelSet2.SelectByPolygon acSelectionSetWindowPolygon, _
varArray, gpCode, gpValue
For Each oAcadEntity In oSelSet2
oAcadEntity.Layer = "0"
Next
Next

oAcadLWPoly is a LightWeightPolyline, so the XYZCoordinates
function just returns a 3D array when passed a 2D array as a
parameter.

The loop runs flawlessly until it encounters this very large
polyline.
Is there a way to add stack space ?

Thanks for helping !

Arnaud