This message is common, especially for first-time importers. It just means there is something inside your import file that Freezerworks thinks you should check before proceeding, like an invalid date format, a spelling error in your Aliquot Type, or a letter inside a numeric field.
Click ‘View Error Report’ for a list of the issues found, and use it as a guide to modify your import file. Before attempting the import again, make sure to close and cancel the import and save the changes in your import file.
If you have a question on a particular error in your error report, contact support for assistance.