Hi every one i am trying to add a new Drop down but i am getting a error that reads

SQL Error : Invalid column name 'call_disposition_c'.

What i did was

1) Admin
2) studio
3) SELECT My MODULES
4) SELECT Fields
5) SELECT Add Fields
6) fill out form (data type DropDown)

and that is the error i am getting SQL Error : Invalid column name 'call_disposition_c'.