Can I use Dynamic C 10.x with Rabbit 3000 processors?
Per Dynamic C Support Resources, the supported version of Dynamic C for the RCM 3000 is 9. The Dynamic C 10 is for the 4000, 5000 and 6000 processors.
Dynamic C 10.x only supports Rabbit 4000 and 6000. You will need Dynamic C 9.62A release for the Rabbit 3000 processor. You can find the release here under ‘view’ https://hub.digi.com/support/products/dynamic-c/?path=/support/asset/dynamic-c-962a-new-release/
Why do you want to use Dynamic C 10? If it is about standard support or better optimizations, SDCC might be an alternative (SDCC is ahead of Dynamic C in those).
However, there are still some features of Dynamic C not yet present in SDCC. And while SDCC 4.6.0 is likely to substantially improve Rabbit support, even then Dynamic C will have more Rabbit support libraries (until someone ports them to SDCC).