It takes off after accepting a purchase with the seller. Need help (Fallout: New Vegas)

When I bought from a seller in the "Red Caravan" and pressed accept (exchange of a cover for an item), the game crashes. I thought that these are typical flights that happen every 3-4 hours, but I load the save again. , purchase, accept and again (crashes). So several times in a row, stupidly I can not buy things.
Who knows how to solve this problem?
(just don't write something like forget it go to another or something like that)