Diagnosis
You are trying to get the switch to which an object is assigned, but theobject is not assigned to a switch.
There are two causes -
1. The object is not yet saved, or not saved to a package (i.e. saved as
a local object).
2. The package that the object is saved to is not assigned to a switch.

Procedure
Depending on the cause above, you can -
1. Save the object first to a package OR
2. Assign the package to a switch and try again.

Procedure for System Administration
You can do the assignment in the transaction SFW1.