If you read the dozens of threads around this problem you will be told that the real problem is that for you to see
EDIT (page) > INSERT > WEB PARTS > CONTENT ROLLUP > RSS VIEWER
you need to turn on:
SITE SETTINGS > TOP LEVEL SITE SETTINGS > SITE COLLECTION FEATURES > SHAREPOINT SERVER STANDARD SITE COLLECTION FEATURES
but you can’t find that feature, and after working with Microsoft Partner Support for 4 days I can tell you that is because it does not exist in FOUNDATION!
Holly Frustrating, Bat Man.
If you want to read the whole painful story and you are a registered Partner with Microsoft, read THIS.