"The Source currently evaluates to an error. Do you want to continue?"
That's OK. Accept it ... in my example, nrA, nrB and nrC were the only acceptable ranges. A and B would be OK, as would a blank cell. Anything else would give that warning.

You can't have a wild card. That would be like saying whatever you put in evaluates to nrC. But it doesn't work.

You would need:
Formula: copy to clipboard 
=INDIRECT(IF($C3="","CostCentre","Division"&$C3))
... assuming there are no spaces between the word "Division" and whatever is in cell C3

Regards, TMS