VLookup Formula Error

My last one returns NAME because no lookup criteria is set for the 2nd VLOOKUP... I based mine off your original but didn't check it, apologies... your first one you see I think has a cell reference missing, see:

VLOOKUP(UPCLookup!ProductMaster!B2:S149824,18,false)

I took out the UPCLookup! as I thought this was an error and didn't think to check you had a lookup criteria, so in hindsight I suspect it should be:

VLOOKUP(UPCLookup!XY,ProductMaster!B2:S149824,18,false)

The above could be wrong in terms of the lookup criteria but that is the source of your problem.