Validation Error

Hi,

I'm adding a field from a staging database into a mart database which is built using SSIS. I've added the field with relevant lookups (the field is called Business) but I am getting the following error from the Source Load Task:

Error 2 Validation error. DFT Load Vacancy: MI Stage Vacancy Source [1]: The output column "Business" (6336) on the non-error output has no corresponding output column on the error output. Vacancy.dtsx 0 0 

The thing is, I've looked and it DOES have a corresponding output column on the error output. Is there something I'm missing here?

Thanks in advance.