What is most likely happen if there was an error during the translation of protein?

The answer depends on the nature of the error. If the error is due a substitution mutation (change in one base pair) in the mRNA no changes may occur as most amino acids are coded for by more than one triplet. However it may also cause another amino acid to be placed in the protein primary structure than the correct amino acid.

If however a deletion or addition occurs in the mRNA (where a base is deleted or added) a frameshift mutation may occur, meaning all the amino acids placed after the mutation will be wrong. 

This means the primary protein structure could be shorter or longer than the correct protein. The protein may not be functional, as a change in the primary structure of the protein (the sequence of amino acids in the protein chain) will change and therefore there may be incorrect folding and bonding in secondary and tertiary structures, altering the 3d shape of the protein.