Crystal Reports Count Shared String Variable

Message

     This is the actual formula in the Main Report:

if {@eSIS CourseCode}={@TableRule CourseCode} or
{EMPCODES.CODE}={@HQ EmployeeCode} then ToNumber("0") else ToNumber("1")
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This is the variable for {@eSIS CourseCode}:
//@MainFormula
//Course code from eSIS subreport
//{eSISdata_csv.COURSE_CODE}
//Shared variable

WhilePrintingRecords;
Shared stringVar eSISCourseCode;
eSISCourseCode

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The variables {@TableRule CourseCode}and {@TableRule CourseCode}are constructed the same as above from subreports.
The field {EMPCODES.CODE} is from the Main Report.

When trying to Count number 1 in the Main report, an error is received that this cannot summaried.  Suggestions please.