I don’t know if this is good enough, but I tried cutting the “bumpy” parts by looking at the curve with Points ON as to see where the bumps starts and ends, and the use Split (Point) and cut the curve where the bumps starts and ends. Then i used BlendCrv and selected “tangent, tangent” in the dialog.
I did this only once, and the mirrored that fixed half of the cog, then joined the halves and finally, arrayed (polar) the cog 20 times.
You can see exactly where to cut when Points are On :
Fig. In this picture I had already made my cut, and pictured is the selected the curve that remained between the cuts, with points On.
I would suggest simplifying the rest of the curve as well (it has way too many control points, and for this reason it’s not going to give you a “good” start for extrusion. The rule of thumb is: as few control points as possible.