Hi there,
It is hard to give direct pointers without the hierarchy at hand.
I can see you are calling the 'parent' of "SuperficieConstruccion" which in theory would be "SubFrmConstruccion"...
either way it should be working if the table in question is a children of this 'parent'
However this method will only remove the data and it won't reset the instances back to original..
If you want to remove all rows you could simply insert an instance on the first index and set instances to 1 like the following:
This process will remove data from the fields in the table without using reset data
I hope this will help.