To measure the distance between two points (point and startpoint) measured along a given curve (polyline, arc, spline...) you can use the free LISP utility - CADstudio LGC (command LGC).
The LGC2 command allows to select a curve (near one of its endpoints) and then it measures the distance of picked points on the curve to the selected endpoint of the curve.
The LGC3 command inserts label blocks (stations) at the picked points (you can also use the "Vertices" option to choose all vertices automatically). The "Relative" option will label releative distance from previous marked point. You can then extract their attributes or schedule them to a table.
You can download the LGC utility from www.cadstudio.cz/download
For advanced dimensioning of lengths and distances along curves, use the newer utilities TraceCurve and DimCurve (see Download and Tips).