Marco wrote:

while making little mistakes here and there. The noun, Patzer, can
be used both to indicate the mistakes themselves or the person who
makes them. I have no idea where it comes from.

Probably cognate with 'patch' and 'botch'.

A botcher is originally someone who sews or mends something
badly or using bad material.

--
Anders Thulin http://www.algonet.se/~ath