Hilary and Anna are right, and they did indeed read the text correctly.
You asked for the meaning of 'incurred', and Hilary and Anna both gave you correct definitions of this word. If you incur costs, you do something which results in your having to pay some money to someone. This might be a bill, a charge or a fine.
Let's take a look at the sentence:
"The council agrees to pay for the full costs incurred by Mr. Wilson."
Subject: The council
Verb phrase: agrees to pay for
Object: the full costs [incurred by Mr. Wilson].
As you can see from this breakdown, the verb 'incurred' does not relate to the subject of the sentence. It is clear that the council did not incur anything - it was Mr Wilson (not the council) who incurred the costs.
If you look more closely at the object of the sentence, you'll see that it's a reduced relative clause. It is a contracted form of "the full costs which had been incurred by Mr Wilson". You'll also see that it's a passive form of the active phrase "the full costs which Mr Wilson had incurred".
There are clearly two stages to this scenario:
1. Mr Wilson incurred some costs.
2. The council agreed to cover (take on responsibility for paying) these costs.
A likely scenario is that there was some kind of disagreement between Mr Wilson and the council or their agents. Mr Wilson incurred some costs, for example, lawyer's bills, during the process of the litigation. When the council was found to be at fault, they agreed to pay these costs on Mr Wilson's behalf.
I hope that is clearer now.