Iulia, I'm sorry you got the email... but... chin up, and chalk it up to experience. There are MANY of us here who applied time and time again (some of us up to 8 or 9 for the one airline!) before getting a job as CC...!!! As Sylphie says, you will also have an edge over the competetion next time (and there WILL be a next time - you know you have what it takes to get past 1st round) you are invitied...
As for your height, while you are waiting your time to elapse before you may apply again... have you considered some of the smaller/regional airlines?? Many of them have a smaller height requirement due to the a/c types they operate.... it may not be Virgin Blue but the experience sure would help!!!
I'm not sure where in Aus you said you're from (sorry just got up after a late night lol) but there are plenty of regionals around Aus, and lots of them are recruiting at the moment (e.g. Rex, Sunstate, QF Link) give them a ago and see what happens. Also, it seems some airlines are changing their ways and going by reach height rather than your actual height... so don't give up!! You did great to get this far out of the THOUSANDS who applied just to be in the first stage...!
Good luck and use this to your advantage, you WILL be there one day!!!
Sky