Field calc failure, division?

[ForrestEnglish]

I'm trying to a percent change for some fields.  I have the amount increased by, and I have the previous value.  So I made a new field, and asked the field calc to [Increase] / [Previous].  It fails, and gives me the following.

General error executing calculator.
ERROR 999999: Error executing function.
Overflow
Failed to execute (CalculateField).

It's a fairly basic operation, and works even on a cheap calculator.  Anyone know what I'm doing wrong?

[DarrenWiens2]

Is there any case where [Previous] = 0? If so, ArcMap gets confused when dividing by 0 (I bet your cheap calculator does, too). Skip over 0s with the code block.

[NobbirAhmed]

Also, make sure the target field type is Double with sufficient storage to hold the resulting value.