Interrupt vector functions must be allocated non banked, say in the 16 bit addressable area.
Error message basically means that the linker would have to cut a 24 bit interrupt function handler address
into a 16 bit vector entry.
So in order to allocate the handler non banked, add a
#pragma push
#pragma CODE_SEG __NEAR_SEG NON_BANKED
before the interrupt handler and a
#pragma pop
afterwards.
Daniel