It works, but it prints the error twice, not sure why.

Turn off PrintError

Won't statements with placeholders (such as SELECT * FROM Table WHERE id = ?) result in a verdict of invalid? Your tool would tell me just about every statement I write is invalid. It discourages best practices.

You shouldn't use a variable for two different purposes. Use a different variable other than $sth to hold the result. There's no reason $sth should even exist outside the eval.