I have seen that error arise in the following situation:
- The e-Recovery is uploaded successfully to the device
- The user is asked to boot into the e-Recovery
- The user does not recognise that they actually booted into the old standard Android recovery …
- /e/OS Installer is given a “click” to move on …
- But of course no e-Recovery is available for the job.
Please check out another eosinstaller similar thread for an image [1] … did you see e-Recovery?
A different device but the above issue is explained Your first boot into Custom rcovery
[1] e-Recovery looks like this