I made a blend of stars and chose the replace with spine command. The stars are not evenly spaced. I then decided to add anchor points and adjust them to try and space the stars evenly. Is there an easy way to distribute these stars evenly along an open path?
While it seems like this should be easy.. it is not. The truth of the matter is, there's no way to control the spacing of objects in a blend accurately. Yes you can add anchors and push/pull handles to try and eyeball the spacing. However on a non-linear path, you'll almost always have uneven spacing in a live blend.
The only way around this is to expand the blend and manually align objects, or expand and use the distribute buttons on the Align Panel.
I see from your follow-up comments that this is a curved path. You said you added anchor points...were you doing that manually, with the Pen tool, eyeballing the intervals? Select the spine and then select Object > Path > Add Anchor Points...do that over and over again, and that should do the trick, though the objects still may not be perfectly spaced apart.