Field calculation based on the field value in an open form

[jaaret]

I am creating a report on quiz results. I'm attempting to add a field showing many times each answer option was selected as a percentage.

The number of times each answer option was selected is in the report's underlying query as [Selected]. The number of total respondents is in an open form: [Forms]![frmQuizzes]![txtResponseCount]. As independent fields, each of these controls display the correct value. However, when I attempt to employ them in a simple calculation:

=[Selected]/[Forms]![frmQuizzes]![txtResponseCount]

The result is #Error.Why is this not working?

 

[jaaret]

Disregard - I closed and re-opened the database and it's calculating correctly.