Passing Subreport Value to Main Report

A couple of things: You have some typos in your code. Here you were missing the semi-colon at the end:

WhilePrintingRecords;
Shared Numbervar EvTotal:= cdbl({Evaluation_Details.NOOFCOPIESEVALUATED});

And here you don't need the semi-colon:

Shared NumberVar EvTotal;
EvTotal

And as @Raphael pointed out, it is important that you have the subreport higher in the hierarchy than the formula in the Main Report that calls the variable. I would also suggest to have "WhileReadingRecords;" in both, that way you ensure they evaluate at the same time. Also, as a little debugging help, put "EvTotal" at the end of the first formula, that way you can see what the value is/should be.