The error simply states that source data is not suitable and make your data suitable for a Pivot Table or make use of the data that is organized as a list with labeled columns. Make sure if you are changing the name of a Pivot Table field, then must type a new name for the field.
Or else if still getting the error, then modify the range. This has helped many users to fix Pivot Table Field Name is not valid error. Check the complete process to change the range of active Pivot Table references as shown.
- In the Pivot table > choose a cell
- The in the data menu > click on PivotTable Report
- After that click on the back button will show the PivotTable Wizard
- Then in the window that shows the > current range for Pivot Table will appear> edit Source Data Range
- Lastly, click Finish > exit the window
Hope this works for you but if not read this: http://www.repairmsexcel.com/blog/resolve-pivot-table-field-name-is-not-valid-error