The archiving reached its Google Spreadsheet limit (of 100,000 cells ) after collecting 9745 Tweets and 5225 Unique Tweets. It managed to run from 26/06/2012 23:20:39 until 02/07/2012 22:45:57 and returned 4010 Links and 4921 RTs.
To continue collecting I could simply restart the process on another Google Spreadsheet.