you want the animation to keep cycling?
in the graph editor select all the attributes in the left hand window thing and then all the keys in the graph (so all points on the curve are selected)
then go Curves > Post Infinity > Cycle
i just tried it out now with a ball on a curve and it worked.
if it doesn't work for you then i didn't explain well enough :p
that's a "Ch" pronounced as a "K"
Computer skills I should have:
Objective C, C#, Java, MEL. Python, C++, XML, JavaScript, XSLT, HTML, SQL, CSS, FXScript, Clips, SOAR, ActionScript, OpenGL, DirectX
Maya, XSI, Photoshop, AfterEffects, Motion, Illustrator, Flash, Swift3D