For people who have the same problem... I fixed this today...
(this is all regarding to the hidden administrator account..)
0) make sure that you dont have pki folder or openssl-easyrsa.cnf file under C:/
1) exclude easyrsa variable from vars
#set_var EASYRSA "$PWD"
2) run init-pki
3) change vars and inclube easyrsa variable (remove #)
4) run init-pki again
5) copy safessl_easyrsa.cnf from C:/pki to C:\Program Files\OpenVPN\easy-rsa\pki
6) open the copied safessl_easy.cnf with a good text editor (like notepad++)
7) use
find & replace to replace ALL
/pki
with
/Program Files/OpenVPN/easy-rsa/pki
8) proceed with build-ca etc.