That way looks good to me.

This part ...
Code:
* this below line is not accepting :ERROR
case >1 to <53
'do some thing
case >53 to < 102
'do some thing..
So On.....
Work something like this into your code, maybe before the CASE part. If the conditions are not met then the code will run to the CASE select part.
Code:
IF (ADVAL > 1) AND (ADVAL < 53) THEN ....