Importing a journal.csv file into Sage.

I have a correctly formatted .csv file to import the general journal from a Quickbooks export, into Sage Line 50. The import starts correctly, but fails at line 50 with a Date error. The date is 01/13/17 - it appears that Sage will not accept any date after 01/12/17 as I have tried deleting the 2 offending lines (as there are two distributions) dated 01/13/17. Any ideas, please?