1. I export role and get a file : ure-roles-backup_2017-04-07_08_34_01.dat.pdf
2. I rename it : ure-roles-backup_2017-04-07_08_34_01.dat
3. I go to a subite press import take ure-roles-backup_2017-04-07_08_34_01.dat.pdf file and get a black error “Wrong nonce. Action prohibitied”
Generally such error takes place when a page was opened some time ago and nonce value generated for this page was expired. Can you repeat this bug with import .dat file once after the opening User Role Editor?
I wonder from where a .pdf extension come. URE exports file with a .dat extension.