Disappearing Line Styles on Splined Polylines

I'm running DraftSight Beta V1R1.4 on Mac OSX 10.6.8 and I'm having an issue with line styles. I'm trying to create curved lines representing roads or paths with varying line styles. To do this I create a polyline with various points, then I use the spline function to create curves / arcs, and then I apply a line style to it (or the one in the layer is automatically applied).

The issue is that I get weird aberrations in tighter curved portions of the lines - the line style turns into either a solid line or dots. See these pictures:

Please help! At this point the line styles aren't really usable for me since they disappear in portions of the line. Thanks!

Joel