No Feasible Entries for Subprogram "rising_edge"
Don't use BIT type, use STD_LOGIC instead. That's probably why you have your error. There is no rising_edge routine for BIT in libraries you are using, but there surely is for std_logic.

Besides, why did you include IEEE.MATH_REAL, IEEE.std_logic_unsigned, and IEEE.std_logic_arith? You are not using it, and actually you should never include the latter two (this packages are not in IEEE standard). Use IEEE.numeric_std instead.