I have never heard of Flarp but I found a good web site for getting it out of clothing. The technique may help with the Flarp on your wall. One way would be to take a baggie and fill it with ice. Take the baggie and place it on the dried Flarp until it is cold. Then scrape it of. The other method that worked best for most of the readers was to take vinegar and pour it on the Flarp. It had to sit on it for a little while. The Flarp then dissolved. One lady had to remove it from her dog's hair. She used vinegar and a wet sponge. She said it worked wonderfully.
Oh my...I hate Flarp. I have a three year old who has recently gotten into a huge mess with this stuff. It was in his hair, on the floor, on the walls, etc. What I found worked really good for the hair was just shampoo and water. It came out pretty easily. Now as far as the walls are concerned I would try some dish soap. I'm not sure how much you need to get out but it worked for me. Just rub it gently and the soap should loosen it up and you should be able to wipe it right off.
The Flarp that we have had (and it has been a lot) has never really dried out. It gets kind of coagulated so this is when you need to throw it out.