Hi:
Generally, every variable used in the TABLE statement must have the variable usage DEFINED in either a CLASS or VAR statement. This is because TABULATE will build "buckets" based on the crossings of the CLASS variables and in the "buckets" it will calculate the requested statistics based on the ANALYSIS variables listed in the VAR statement.
Based on the table statement you showed:
[pre]
table course_name, department*section*tot_cost;
[/pre]
I figure that COURSE_NAME, DEPARTMENT and SECTION will be your CLASS variables, and will appear in a CLASS statement and that TOT_COST will be your ANALYSIS variable and will appear in a VAR statement:
[pre]
class course_name department section;
var tot_cost;
table course_name, department*section*tot_cost;
[/pre]
Double check your syntax to make sure your TABULATE code has CLASS and VAR statements. If you do have CLASS and VAR statements in the code and you are still having problems, then your best bet for help is to contact SAS Tech Support.
cynthia