Security Deployment Tool not installed prior to applying change package..What now?

Created a changed package using Image 18.  The job is at the 88% completed step where it runs into the 'Updating Security' steps.  Unfortunately, I wasn't aware of the change in deploying security.  So, I saved my job and tried to go in and create a new change package with the security deployment bug.  Unfortunately, I cannot get CA to let me not finishing (or possibly deleting) the original change package from Image 18.  Is there a way to apply a 2nd change package before I have finished my first change package?

I have found many times in documentation where I've started updating or installing something only to get partially thru and see a phrase like - 'Before you start this update, make sure you done X and Y (I see it in the year end tax updates every year), there was something that I did last week - which I can't remember - that had the same type of thing...and now this.  If there is something that HAS to be done prior to me starting something, I wish that it was in STEP 1 - or as far as this goes,