This raises several questions:
Protsch's work seems to be a major part of the evidence for the recent finding that Neanderthal Man lived in the extreme cold of Northern Europe at times when it had previously been assumed impossible. The existence of Neanderthal Man in Southern/Central Europe and the Middle East remains undisputed unless you have a scoop.
If Oxford is right that these Neanderthal bones were only 7500 years old, then what does that do to our understanding of Neanderthal? Do existing models have Neanderthal living as recently as 7500 years ago.
Most of the dates mentioned would be more likely Cro-Magnon than Neanderthal.
I believe the only "Northern Neanderthal" on this chart is the Hahnofersand specimen, now dated at 7,500 years old, previously trumpeted as an "advanced Neanderthal" and a possible hybrid. Of those links, however, this ARN page lists it as an H. sapiens specimen.
How easy is it for others to commit the same mistakes this researcher made?
Typically, you have to earn some trust before you can abuse it but there are historical exceptions. Two people named Clinton come to mind.
Have new techniques questioned enough results of the old techniques, that perhaps all prehistoric bones should be retested using the new techniques?
I don't think so. Ask your butt why it thinks this is a question.
In other words, how big of an indictment is this really?
Of the individual? Pretty big.
Is it just one guy or is it the whole field of study?
Could it be you just don't like the answers since about 1859?