"A42 error : UNDEFINED IDENTIFIER" error when compiling an assembly module

i am getting "A42 error : UNDEFINED IDENTIFIER" error when compiling an assembly module. when i click on the error it indicates it to statement that contains the defined variables.
i am compiling for XC164CS controller

the part of the code where i am getting the error is inserted below.

;FUNCTION: FirstSample -----------------------------------------------------------------------------------------------------
public   FirstSample
FirstSample proc
;Set next Sample routine
 ->  mov   SampleRout,#SecondSample

i am getting the error where i have put an
"->" above.
both the variables are defined and i am unable to find the problem. is there any other reason for this problem.
is there any problem with the operands of the "MOV" instruction.