Linkshare has just posted this announcement:

Beginning September 1, 2007 all data prior to August 31, 2005 will ONLY be available in SynergyAnalytics and not in the Interface Reporting System. Going forward, each month we will remove one month’s worth of historical data from the Interface Reporting System. For example, on October 1, 2007, you will not be able to view data prior to September 30, 2005.