Translation:Please don't take money.
I think it's just the な gobi.
No, but this is not a ru-verb. Verbs that end in る are only ru-verbs when the sound before the る is a "i" or "e" (ex. せ、め、み、ね、り、い、え, and so on). In this case, it's an "o," whivh makes this a u-verb that happens to end with る. To make a ru-verb negitave, you remove the る and add ない (ex. 食べる = 食べない、見る(みる) = 見ない).
Japanese often omit the subject due to the context;
And in this case, I think it is possible that the money is found on the street, so basically nobody knows who owns it.
Japanese people would normally take the money to the nearby police station rather than take it for themselves.
In English it'd be like: Please just don't take the money.
rather than: take my money or his money.
Today I have found a very good explanation of ないで and なくて (for verbs - for nouns/adjectives it is always なくて).
In short, if there is a natural connection between two clauses, use なくて, and if there is a strong relationship between the two clauses, then ないで (except for the reason usage).
When I have time (or someone else who agrees what the people said in the link above), I (or s/he) will add some more explanations...
I kind of disagree on that one. It's more natural in English to say any. I too put that "Please don't take any money" and it was marked wrong. you could also say "please don't take the money" and it could also be correct in this case, but without context it's hard to know.