N80i + ShoZu + Tom Tom GPS works 50% of the time -N80i, S60, ShoZu, or Tom Tom bug?

Using a borrowed Tom Tom Navigator 6 GPS from Cyprien (thanks!), I did a little outdoor GeoWalk from Bryght at 1 Alexander to the Vancouver Art Gallery, I took 29 photos with my Nokia N80i. Only roughly 50%, 15 out of 29 were geotagged, shouldn't that number be 100% or closer to it?

Is this a S60, N80i, ShoZu, or Tom Tom bug? Suggestions to make this closer to 100% gratefully received.