The "thank you very much for your disinterested help" comes across as sarcasm. I was a bit offended by it but then I decided to assume that you meant "thank you for taking the time to help even though it's not your project".
I'm not paid to help people on the forum so it's true that I don't have the same level of interest in getting your project working as I would with my own. However, I did take the time to open your attached image of the error message, download the Button library, unzip it, and check to see if it had the PushButton.h file, then looked at the open-trip repository and the author's blog to see if I could find a link to the library that had that file. So I think "disinterested" is not quite accurate. I did stop short of doing a Google search like TomGeorge did since I figure you're just as qualified to do that as I am.