Lee Spetner has some false arguments. Some time I'll nail down exactly what's wrong with them. For starters:
His computations on the page mentioned above are orders of magnitude off. He confuses point mutations with all mutations. No biologist today is unaware of the evolutionary importance of transposons!! Geepers! Get modern! Also there are often several ways a mutation can occur. Furthermore, there is a process called recombination that allows rare mutations to be brought together. Does Spetner know that the reassortment of genes and gene clusters is thought to confer such an advantage that it is probably the explanation of why almost every species --- from virus to bacteria to animals and plants --- has sex?
But just look at the wonderful recent literature on Green Fluorescent Protein (GFP)! They did mutation and selection to create things like Blue Flourescent Protein. Also, people have been selecting mutations of all kinds for more than 50 years. He needs to learn a little molecular biology and a lot of WELL KNOWN genetics!
Also, the rate of mutation is set by evolution! T4 DNA polymerase has mutations that not only increase the rate of mutation but also decrease it. This is completely consistent with Shannon's Channel Capacity theorem, as revised for molecular biology. The theorem states that molecular systems that function at the channel capacity (eg rate of DNA synthesis per second) can have as few errors as necessary for survival.