Thanks for the info.

I will try deleting the register and replacing it. Although it works when the owner tends the register. I guess I will play with it a little more to work it out.

Not the register, the objects you are selling on those pedestal, shelves, rugs of any. Are there any that your trying to sell that's not from the game itself. Read the link which items you can sell through the Savvier Seller mod.

I am only using the parking spaces and selling vehicles. On the Mod FAQ page it just talks problems selling things that are not from buy mode. Do the vehicles sold have to be the original game content or can they be modded content? And it has only happened when a store clerk is assigned. If I make the lot owner tend the register every thing works like expected and cars are purchased. I don't have to restock because the "display" cars are not physically taken by the purchaser. I will also try removing the savvier sellers mod all together because I am also missing the option to check the sales performance. I think I need to see how the content works on its own with out a mod.

Elena Devore is corrupt, possibly due to out of date mods as J4Ks noted. I would make sure every tuning mod is up to date along with scripting mods.

Okay I just found your other error and that one is related to the mod. I believe that one occurs when it can't find anything for sale in the room that the register is in. Would that apply to you?

It may apply, the lot is set up as a building with 1 car on a SS parking space inside the building and about 10 cars outside of the building on SS parking spaces.

Try making sure something is for sale in the room with the register and see if continues to error.