Actually, the issue of Julia and Angelique's curse is already a huge quandry in and of itself because the curse states that anyone who loves Barnabas would die - not necessarily anyone that he loved. Julia's love for Barnabas is quite evident, so by rights she should have died. Trying to justify why she didn't has provoked many interesting debates through the years.
Even Angelique died from the curse she placed on Barnabas, but she actually said the words I love you to Barnabas.
So in regards to Julia. I always thought that perhaps the curse had no effect on Julia because she never actually came right out and told Barnabas I love you.
Just a theory.
Although the real reason was that Dan Curtis wasn't about to kill Grayson Hall's Julia character off the show . Sam Hall talked about that in one of the DVD's interviews.
FireRose