Have you found a solution for this problem? I am dealing with exactly the same thing.
Does one of the cost attributes on your network dataset have a space or other special character in the name? I've seen that "specified column does not exist" message in that circumstance. If your network does have a cost attribute like that, rename it to something with only letters, digits, and underscores, rebuild the network, and try your solve again.
no I don't have a space or a special character in the name of my cost attributes.
Hi, in the end there was an error in the name of my cost attributes. It wasn't in the attribute table but in the Network Dataset Properties, Attributes tab.