This issue is tracked under Bug Number LCRM-23285. In that bug, the AccountDonationList Visualforce page shows a list of donations where donor proxy contacts on Organization Account Records are soft credited. This VF page doesn't work on household accounts (You get an SObject error).

Follow these steps to remove that element from your page:
  1. Go to any Account record.
  2. On the upper left of the account record, click Edit Layout (as seen here:
  3. Once editing the layout scroll down to the Account Soft Credit section and hover over the AccountDonationList Visual Force Page. Click the circle button to remove the visual force page (as seen here:
  4. After removing the AccountDonationList visual force page, click Save on the upper left of your screen to save the changes.