I have set the fiscal year under administer->Localization->Date Formats. However, when looking at Summary Fields, it continues to calculate only calendar year contributions for the Total Contributions this Fiscal Year category. How do I correct?
Summary fields creates a collection of custom fields that it populates. It populates them when you first set the extension up, and then it also updates them as new contributions are stored.
I suspect that it doesn't recalculate all the fields when you update your fiscal year, you probably need to ask it explicitly to do that, eg. by resaving the configuration of the extension.