Right, excellent question. We should put something in the FAQ. It's going to take some time to answer properly, but here are some initial pointers. Note that while I know Erlang academically I am definitely not an expert, so feel free to add more comments if you like.

Both languages are based on message passing, but Erlang is functional whereas Jolie is classical imperative/stateful.

Jolie provides architectural programming, e.g., you can make proxies abstracting from the behaviour of what you are composing with a language primitive.

Jolie provides integration natively, e.g., with automatic data transformations between different data protocols. The contract with the developer is that if you need to change protocols or deployment information (e.g., switch from TCP/IP to Bluetooth L2CAP or in-memory communication), you just have to change a couple of lines in the deployment part of a Jolie program and the rest will continue working without modifications to the program logic (logic/deployment decoupling).

Jolie has dynamic fault handling: fault handlers can be updated at runtime compositionally (higher-order code composition), which is afaik a new thing.