Hi Adrian,
When things go wrong with global security and you can't reach admin console
as you told above, you can turn security off using wsadmin utility;
then,on interactive command line,
then restart your server again and global security is turned off and admin console is reachable again.
It seems to be a little late for you this time, but may save you from some headache next time
Wishing you patience and good luck
Kurtcebe Eroglu