Did the Workflow Monitor crash?
Or did indeed the repository service crash?
If it's the workflow monitor: did you upgrade both server and all clients from 10.1 to 10.1.1?
If it's the repository service: what messages do the logs of the repository service, the node, and the domain contain?
we face the same issue, as well with 10.1.1
is this fixed with some new hotfix, or 10.2?
When it comes to crashes, the best option is to open a case with Technical Support. You will probably be asked to provide the process core dump's stack traces in addition to the application logs.
As mentioned by Nico, First find whether Repository Service is crashing or PowerCenter client is crashing so that we can help you in troubleshooting the issue accordingly.