jam9_secretagent,
I suspect that you have either manually created polygons with more than four sides, or possibly you have bevelled/extruded/mereged points and still have a number of 1 or 2 point polys left behind from the process.
Here's what to do:
In modeller, with the object loaded, go into polygon selection mode (Ctrl-H) and open the polygon statistics panel (w).
In here, you will see a list of the polygons that are in your model along with their number of points (as below):
Here, click the + icon to the left of any one or two point polygons and then delete them (this is a safe action and won't destroy your model). For any with >4 vertices, you will need to select these and remodel the area they are in. Either by deleting and recreating the polygon, or selecting the polygon, going to point mode (Ctrl-G) selecting pairs of points and hitting split (Ctrl-L).
As far as possible, try to aim to get 4 point polys into your model for working with subpatches as triangles can have more of a tendency to pinch. Also, try to only get four polys to share a point where possible to avoid any pinching.
Hope this helps,
Mark