Going through the error messages, there are a couple of issues.
First, your code seems to only create output for ONE problem, even if there are more.
Second, the “to many problems” error is invoked when there aren’t to many problems. Meanwhile you are not throwing an error when the operator is “/” (but only + and - are allowed).
Errormessages can be a bit daunting at first, as there is a lot of text.
But they go something like this