A ruling excluding evidence shall not be set aside, nor shall a judgment or other ruling be reversed as a result of the erroneous exclusion of evidence unless:(1) The evidence was erroneously excluded although the character, purpose and relevancy of the same was brought to the court’s attention through an offer to produce evidence or otherwise, and(2) the court passing upon the effect of the erroneous exclusion is of the opinion that it was a decisive or substantial element of the judgment or ruling whose reversal is sought.
Puerto Rico Legal Code