data view

i have an 05 plc withan analog input / output card 4-20 ma . when i try to view the vmem locations i have setup i get 0 at my raw locations using pointer setup . all this is ok the problem is when i click from one address to another in data view i get ? marks in the status and edits coloum what does this mean ?

If you put an invalid address in the dataview it shows ????
V2000 is a valid address 2000 is not