Probably uint8 is not yet defined?
It would be rather helpful, when you tell at least in which line the error occurs (second extern?)
A complete file or even the project would be appreciated as well.
§ 1: The compiler is always right
§ 2: Should it be that §1 happens to be wrong, automatically §1 drops in.
I've always hated these C-compilers for their rather cryptic, sometimes mis-interpretable error-messages.
PS: By the way: Why not putting the sine-table into program-memory. It is rather doubtfull that the values will ever change during the lifetime of the project and it would save some (precious) RAM.
Plse excuse my typos, but that cat will not take its paws off the kzboard.