OVPN error

C:\Users\Administrator>cd %ProgramFiles%\OpenVPN\easy-rsa

C:\Program Files\OpenVPN\easy-rsa>vars

C:\Program Files\OpenVPN\easy-rsa>build-key-server server
Generating a 4096 bit RSA private key
................................................................................
................................................................................
..........................++
................................................................................
................................................................................
................................................................................
................................................................................
...............++
writing new private key to 'keys\server.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [US]:
State or Province Name (full name) [CA]:
Locality Name (eg, city) [SanFrancisco]:
Organization Name (eg, company) [OpenVPN]:
Organizational Unit Name (eg, section) [DSANFRAN]:
Common Name (eg, your name or your server's hostname) [DSANFRAN]:server
Name [DSANFRAN]:
Email Address [dmg12@gmail.com]:

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:
Using configuration from openssl-1.0.0.cnf
3428:error:02001002:system library:fopen:No such file or directory:crypto/bio/bs
s_file.c:74:fopen('keys/index.txt','r')
3428:error:2006D080:BIO routines:BIO_new_file:no such file:crypto/bio/bss_file.c
:81:
Could Not Find C:\Program Files\OpenVPN\easy-rsa\keys\*.old

C:\Program Files\OpenVPN\easy-rsa>