Always the same error message with my Archos smartphone helium under andoid 4.3 and 0.5.4 Apk PirateBox?
The smartphone user root on vroot?

Unsupported device!
-Device not rooted
-Backup for "dnsmasq"could not be created

Hi,
seems like the

su

command is not found on your device.

how to remedy it?

Try to install SuperSU, that might fix it.

After installing supersu root mode version 3.1 works but still the same error message with the higher versions until v0.5.4.