Did you get a new set of licences for BE 2012 and apply them after you have upgraded to BE 2012? BE 2012 uses .slf files for licences. Your BE 2010 licences will not work with BE 2012. If you are on a current maintenance contract, you can get the BE 2012 licences from Symantec Licencing for free.
After we upgrade it it was renewal time and we renewed licenses to 2012 edition, "SYMC BACKUP EXEC 2012 AGENT FOR APPLICATIONS AND DATABASES WIN PER SERVER RENEWAL BASIC 12 MONTHS GOV BAND S" but when we activate license system says that the license is under maintanance..I don't understand what is the problem..