#value when editing userform

HI

I have this userform whereby I am capturing information that a has a

1. Unit price
2. Quantity
3. Value

When I edit the data on the userform to update information, the Value Column in the Spreadsheet returns # Value. This happens for all records.
I am not editing the value field at all. The only time I will edit the value column is when there is 0 value.
How can I overcome this issue.

Thanks