Error File Checksum Failed
A checksum error means that one of the project data files (on the ".data" project folder) has been modified since the project was saved. You can "ignore" these problems by simply removing the checksum from the XML code.
If you remove the sha1 attribute, the project loader won't verify the integrity of the image in question. Bear in mind that this may lead to further errors if the image is inconsistent with other project items.