New modder, confused by index error

[ShadowMonkey]

As the title says I am a new modder, I just made my first few mods (couple of shirts, a slider, and some mesh mods.

 

After making couple of mods I tried using Sims 4 studio and that forced me to download an older version of blender.  Everything worked well until I went back to using TS4 Morph Maker to try to update my slider and make a new one. Now I am getting an error "Index was outside the bounds of the array"  I have trialed and error'ed various vertex points and can't seem to make any logic out of it.  I can still remake my original mod no problem but any modification of it seems to cause the same error.

 

Anyone know what is causing this? Are there rules for mesh mods besides the number of vertexes I need to be aware of?  Did I break TS4MorphMaker by using an earlier version of Blender to get Sims 4 Studio to work?