Yep, it’s looking for recorder.conf so it can write in it.
Out of interest, I just ran into this issue and was fairly confused until finding this topic. It would be great if this was in the documentation.
For the record, using sbt 0.13.9, scala 2.11.7 and gatlin 2.1.7
I improved the message: https://github.com/gatling/gatling/issues/2866