My guess is, you've hit a resource cliff, over which the server falls when this task runs.   This is a good time to review your overall resource usage on this server, as well as the task itself to see if there are things that take place in parallel that might need to not do that, or if there's been large growth in one of the affected databases, that now causes the re-org to consume considerably more RAM.    What kind of server do you have?  Physical or Virtual Machine?   Total RAM?  Overall size of all the databases on this instance?