Updated AMLightweightScanInfoCollection::populateSampleNames() ~ The query string now includes a WHERE clause to specify sample IS NOT NULL. It turned out that it wasn't query.next() that was at fault, but the fact that I was getting samples used by entries in AMScan_table. Because these might be empty, the potential for empty results to be returned existed which the collection would then add to the list of known samples. The following attempt to load these from the sample table would produce the error. Only returning samples from AMScan_table which are NOT NULL fixes this.