Hey @RayO, thanks for reaching out!
Short answer: do this Configure Build Environment for Torizon Containers | Toradex Developer Center. You may also need to apt-get install qemu-arm-static.
Long answer: exec /bin/sh: exec format error happens when you don’t have binfmt_misc enabled in your Linux system, which is a kernel capability that makes it possible to execute binary files from a foreign architecture (in this case arm) from - in this case - x86 native machine. The steps above will basically tell your Linux something along the lines of “if you detect I’m trying to run an arm binary, please run it using QEMU instead of trying to natively execute it”.
Hope that helps!