My world is broken!
If a world cannot be loaded than this can have two causes: Either the world itself contains an error (invalid XML or JavaScript with a syntax error) or a module required (loaded) by that world includes an error. What can you do?
Visit an old version: To visit an older working version of that world, select one version from the list below and click visit. The world will load in a new window. Also old version of modules will be used so if a broken module caused the error than you will be able to use the world. Try the list entry second from the top to visit a version that normally should work (it's the second newest version).
Revert the world: Select a version and hit revert. The world will be re-saved. If a module caused the error than the reverted world will still not load.
Revert/fix the module: If a module had caused the error (the error message and its location/stack will help you to find out the moduled needs to be fixed. In that case yo ucan eiter edit the module using the system browser or revert the module. For that, enter the module url into the Version Viewer below and hit revert.
If you cannot solve the problem please write to the Lively mailing list.