What computer operating system is your Premiere Elements 12 running on?
Can you click Continue to continue in the program after the message appears?
Have you updated 12 to the 12.1 Update using an opened project's Help Menu/Update? If not, please do so.
Are you installing from installation files from a purchased online download or from an installation disc
from purchased boxed packaging of the product?
Have you done the uninstall reinstall by the following scheme
a. uninstall the program the usual Control Panel way
b. do a free ccleaner run through (regular and registry cleaner parts) to get rid of any leftovers from incomplete installs and reinstalls
c. reinstall the program with the antivirus and firewall(s) disabled
Please review and consider the above and then let us know the outcome.