a question about digital clock

i've used a schematic file to creat a 24 counter and used a vhdl file to creat a 60 counter.they all simulated sucessfully ,and i've created symbol file for vhdl file.but when i use symbols in a schematic file to creat a digital clock,it can't compile.it shows:

Error: Node instance "inst" instantiates undefined entity "cntm60" (60 counter)

Error: Node instance "inst1" instantiates undefined entity "c24" (24 counter)

and when i double click the 60 counter's symbol or 24 counter's,it shows "no vhdl file"