#Error Message In Result from 2 dates

[Hazel]

I have a

date received field
and
date completed field

I have an expression that works out the no of working days it takes to complete

Problem is that although the date received will always have a date entered i have to wait until i receive the dates to enter in the date completed field, thus my field that calculates the no of days has #error in the field how can i get rid of the #error in field as i dont want this to be seen.

Hope someone can help

 

[Mile-O]

=IIf(IsNull([DateComplete]),0,YourFunction([DateReceived],[DateComplete]))

 

[Hazel]

=IIf(IsNull([DateComplete]),0,YourFunction([DateReceived],[DateComplete]))

Thanks for that