vicnza

I did the above and it said "update successful" but whenever I make a sell I get an error " Synchronization error quan" what does that mean?

I have synched Copper and Inventoria and received a message that says "update successful" but when I go on the inventoria the items which I had created on copper are not synced in inventoria, also whenever I make a sale, copper tries to synch and throws out an error "Synchronization error quan " what does this mean and how do I make sure that this works? I am running a demo version of inventoria with copper POS on a mac.