  Computational thinking is increasingly introduced at primary school level,
usually with some form of programming activity. In particular, educational
robots provide an opportunity for engaging students with programming through
hands-on experiences. However, primary school teachers might not be adequately
prepared for teaching computer science related topics, and giving feedback to
students can often be challenging: Besides the content of the feedback (e.g.,
what problems have to be handled), the way the feedback is given is also
important, as it can lead to negative emotional effects. To support teachers
with the way of giving feedback on common problems when teaching programming
with robotics, we conducted a study consisting of seven workshops with three
third and four fourth grade primary school classes. Within seven different
activities, the 116 primary school children first programmed the Ozobot Evo
robot in the pen-and-paper mode and then on a digital device. Throughout these
activities we collected data on the problems the students encountered, the
feedback given, and the fun they experienced. Our analysis reveals eight
categories of problems, which we summarise in this paper together with
corresponding possible feedback. We observed that problems that are urgent or
can harm the students' self-efficacy have a negative impact on how enjoyable an
activity is perceived. While direct instruction significantly decreased the
experienced fun, hints had a positive effect. Generally, we found programming
the Ozobot Evo to be encouraging for both girls and boys. To support teachers,
we discuss ideas for giving encouraging feedback on common problems of Ozobot
Evo programming activities and how our findings transfer to other robots.
