I presume that on an individual Parent record, you probably have less than 100 children,s o you are probably OK there. But you are asking if you try to map all records, there are too many. That is just a current limitation of QuickBase. It only lists the first 100 records, but some definition of "first".
If you need to map more, there are enhanced add-ons like from Juiced Technologies which are not limited to the number of pins and also have other features such as being able to color and label the pins by formula.
http://www.juicedtech.com/add-ons/qb-maps