Gavotte, you should have just asked me but that's ok, the forum is a great place.

Carrara has had this weird glitch in it for the last several versions.  The fix is simple.  Just use the convert point tool on the end point of the extrusion path.  For some reason, Carrara is inverting that last point perfectly by 180 degrees (it's kind of like a negative zero, it's still zero but negative).

Regardless, it will flip it and straighten it out.  If that doesn't work, actually convert the point to a smooth point and set it to tweeny eeeny eeny (like 0.00001) and that will also work.

-Kix