Will working with sharepoint you may find yourself in a situation where your webpart blows up and you will not be able to access your page. You cannot fix page as design options are available for editable pages in design mode.
There is an option to remove webparts from these page to make them working. Providing query parameter Contents=1 will redirect you to WebPart administration page for selected page. This page will provide you options for removing webparts.
e.g. your page link was as follows
Opening following url
will allow you to fix your page.