When attempting to edit a posted pledge that had been previously adjusted (and the adjustment posted to the GL also) the error "Data could not be saved. ERR_FINANCIALTRANSACTION_LOCKEDFIELDS" is thrown. This error can happen when attempting to change the appeal or the installment schedule.
This is a data specific problems and there are at least two causes of this error. Please contact customer support or create a case if you're encountering this issue for additional information and a potential script fix.
Steps to Duplicate
1. Go to the post pledge record. 2. Click Edit posted pledge > Change the appeal or installment schedule > Save 3. Notice the error is thrown.