Basically that bow cannot be repaired. The level needed to repair that bow is much too big. But basically, to repair a bow, you do what you did. Put another bow in an anvil and repair it which costs levels.
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If its not enchanted, put it in in the crafting with a different bow that damaged, it will make it higher in durability(the bar will go up). But if it is enchanted, make a new bow and put it in with an enchanted bow, but rename it.
My guess is that the bow have been repaired multiple times before. Everytime you repair something the level to repair it grows higher to the point where it can not be repaired. If you give a bow a nickname it will remain the same level of repair every time.
Just to note - renaming an item will not stop the repair cost from increasing in current versions, not since 1.8 (otherwise, you can save an item which is too expensive by renaming it since the cost of renaming is capped to 39 levels and it will reduce the penalty to 2 levels; of course, this assumes it can be repaired at all (the bow shown can be fully repaired for 33 levels if renamed) because back then you had to pay for the durability restored (this means a damaged sacrifice will be cheaper, particularly for diamond tools, which cost up to 17 levels for the repair itself, while a bow costs up to 4 levels) as well as the cost of all the enchantments on an item when you repaired it, as opposed to only 2 levels plus the prior work penalty in current versions - not that you'd want to repair items in the anvil when there is Mending).