Using Calcdate

CALCDATE should only be used with DateFormula variables. Alternatively the string should be enclosed using the <> symbols.

Bad code

IF ReservEntry."Expected Receipt Date" >
    CALCDATE('-' + FORMAT("Dampener (Time)") + FirstDate)
THEN

Good code

IF ReservEntry."Expected Receipt Date" >  
    CALCDATE('<-' + FORMAT("Dampener (Time)") + FirstDate + '>')  
THEN