"If (Not IsNull ({tblServiceOrders.TimeReceived})
   and Not IsNull ({tblServiceOrders.TimeRequested})) then
ReceivedToRequestedTimeAdjustment := ((ToNumber ({tblServiceOrders.TimeRequested} [12 to 13])) * 60) + ToNumber ({tblServiceOrders.TimeRequested} [15 to 16])
    - (((ToNumber ({tblServiceOrders.TimeReceived} [12 to 13])) * 60) + ToNumber ({tblServiceOrders.TimeReceived} [15 to 16]));"

 

The error is saying "A string or an array of values is requested here." for the first "ToNumber({tblServiceOrders.TimeRequested}"

 

How do I fix this?

DBlank asked you the field type, I doubt, the field which you are refering could be a string type or a time filed.

 

If that is a string field then try  IsNumeric() in your if condition.  If not let us know what is the field type

 

 

 

 

"", &

 

I don't remember if you need single quotes surrounding whatever is after the ampersand...but you can type it in and then try to verify if it fails, then add the single quotes