Ok,
you just don't understood our first hint. Here is the second:
Put your cursor inside the word "serout" (using the MCS),
hit F1,
read the help.. ! (or look at your pbp-manual!)
There is an "include xxxx" in red letters after the first paragraph !
Use it !
You use the constand N2400 in your 3rd line, which is not declared...
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