To ensure reliable performance for all advertisers during advanced URL upgrades, the AdWords API has placed a temporary limit on the number of AdGroupAd
During most normal operations, you won’t run into these limits. However, if you are uploading a very large amount of new ads in a short period of time and find yourself running into this error frequently, let us know on our forum and we will work with you to address the issues.
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operations that can be performed on an advertiser account per day. Other types of requests are not affected by this change. Please review the RateLimit documentation and make sure your code handles the RateExceededError properly.During most normal operations, you won’t run into these limits. However, if you are uploading a very large amount of new ads in a short period of time and find yourself running into this error frequently, let us know on our forum and we will work with you to address the issues.
from Google Ads Developer Blog http://googleadsdeveloper.blogspot.com/2015/06/temporary-limits-on-ad-uploads-in.html