If you go to options menu - Native draw is it set to GDI mode, if so this is no good for rendering, it needs to be set to RedSDK, if it needs changing make sure to save your file first as it needs a restart to change modes.
If already in RedSDK mode, right clicking the render teacup (icon) one can make sure the draft rendering is set to RedSDK not open gl.
Failing all that, you could post the TCW file for someone to check.