Google announced that in the next few weeks, they'll finish the transition and retire Report Center entirely. From then on you'll schedule and download reports from within AdWords campaign management.
"We've made the transition gradually, to help, we've added relevant FAQs to download menus in Campaigns tab, enabling you to find the views and metrics you're interested in more easily.
If you're currently downloading reports from Campaigns tab, you've already adjusted to bulk of changes, and you'll find that each of your scheduled reports have been copied to Control Panel & Library. We'll delete any old versions of scheduled reports from Reports tab, and stop sending emails associated with them, by early November. Shortly thereafter, we'll remove Report Center entirely," Google informed.
To prepare retirement, you can compare the scheduled reports in Reports section of your Control Panel & Library to old versions of your scheduled reports in Report Center, then make any necessary adjustments to make sure you're getting the data you want, in the format you want.
More Info: AdWords Help Center