Are you really using Responsive Sheffield v1.0? You've been posting the same things in both the 1.0 and 2.0 threads. Which one are you actually using? Best to keep the discussion in the thread for the one you're REALLY using.
As for that specific ajax message, you're using a template designed for an older version of Zen Cart. See: Making v154 DIY/Picaflor-Azul templates work with v1.5.5
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