Signal output cannot be synthesized, bad synchronous description.

Hi,

This is the whole code which I am working right now:

process(clk_plstr,plsrep)

begin

if(plsrep='1')then

count_reg<=B"000";

end if;

if(clk_plstr'event and clk_plstr='1') then

count_reg<=count_next;

if(count_reg<=pls )then

output<='1';

else

output<='0';

end if;

end if;

end process;

count_next <=count_reg+'1' when(count_reg=B"000" and plsrep='1') else

count_reg when (count_reg=B"000") else

count_reg+'1' when (count_reg<pls)else

--count_reg;

B"000";

fout<=output;

end Behavioral_plstr;

It might be I have done some silly mistake.

Thank you.