I appreciate this project is no longer being updated, but leaving here incase it helps anyone else.
We started to encounter an exec format error when control tower was downloading external binaries on install:
fork/exec /home/ssm-user/.cache/control-tower/bin/d2f1bcdabd547b8c31f8c20e6f0bd990a1b24cbfd0d549cf1873cb383fe531f9: exec format error
We were able to track the issue down to control-tower trying to download bosh-cli from an s3 bucket that no longer exists. I've left a comment with how we fixed that using a locally compiled control-tower binary here: concourse/concourse#9002