Trouble with updating a specific row in my recordtype using a!update

I want to update a specific row in my recordtype with data in one of the columns as follows: 

Here I am using my id (the primary key of the table) to specify which row I wish to update, in this case i want to update case number 80 and update the casestatus column with "accepted", however upon doing so I get the following error: 

I am guessing that my syntax is incorrect, but I can't seem to figure out what I am doing wrong exactly.