The most blatant English error I noted in Abba lyrics is saying ‘funny’ when they mean ‘fun’. This happens twice: “Must be funny in the rich man's world” and “You can dance with me honey, If you think it's funny”. There are at least a couple of words in Swedish (‘roligt’, ‘kul’) that can are used both meaning fun/pleasant/enjoyable and funny/amusing/hilarious, so Swedes sometimes confuse them.
I'd always taken that to be it must be odd being in a rich man's world with all that money if you're not used to it. The lifestyle, choices and pressures are so different.
It never occurred to me it meant it was fun. I've never studied the lyrics so there is a good chance I've missed the point anyway.
