A user on Vista updated to 2.3.10 and cannot connect anymore:

Wed Jan 13 17:43:36 2016 OpenVPN 2.3.10 i686-w64-mingw32 [SSL (OpenSSL)] [LZO] [PKCS11] [IPv6] built on Jan  4 2016
Wed Jan 13 17:43:36 2016 Windows version 6.0 (Windows Vista)
Wed Jan 13 17:43:36 2016 library versions: OpenSSL 1.0.1q 3 Dec 2015, LZO 2.09
Enter Management Password:
Wed Jan 13 17:43:36 2016 MANAGEMENT: TCP Socket listening on [AF_INET]127.0.0.1:25340
Wed Jan 13 17:43:36 2016 Need hold release from management interface, waiting...
Wed Jan 13 17:43:37 2016 MANAGEMENT: Client connected from [AF_INET]127.0.0.1:25340
Wed Jan 13 17:43:37 2016 MANAGEMENT: CMD 'state on'
Wed Jan 13 17:43:37 2016 MANAGEMENT: CMD 'log all on'
Wed Jan 13 17:43:37 2016 MANAGEMENT: CMD 'hold off'
Wed Jan 13 17:43:37 2016 MANAGEMENT: CMD 'hold release'
Wed Jan 13 17:43:47 2016 MANAGEMENT: CMD 'username "Auth" "username"'
Wed Jan 13 17:43:47 2016 MANAGEMENT: CMD 'password [...]'
Wed Jan 13 17:43:48 2016 Control Channel Authentication: tls-auth using INLINE static key file
Wed Jan 13 17:43:48 2016 Outgoing Control Channel Authentication: Using 256 bit message hash 'SHA256' for HMAC authentication
Wed Jan 13 17:43:48 2016 Incoming Control Channel Authentication: Using 256 bit message hash 'SHA256' for HMAC authentication
Wed Jan 13 17:43:48 2016 Socket Buffers: R=[8192->8192] S=[8192->8192]
Wed Jan 13 17:43:48 2016 MANAGEMENT: >STATE:1452703428,RESOLVE,,,
Wed Jan 13 17:43:48 2016 UDPv4 link local: [undef]
Wed Jan 13 17:43:48 2016 UDPv4 link remote: [AF_INET]193.175.73.200:1194
Wed Jan 13 17:43:48 2016 MANAGEMENT: >STATE:1452703428,WAIT,,,
Wed Jan 13 17:43:48 2016 MANAGEMENT: >STATE:1452703428,AUTH,,,
Wed Jan 13 17:43:48 2016 TLS: Initial packet from [AF_INET]193.175.73.200:1194, sid=5b759195 5e14f268
Wed Jan 13 17:43:48 2016 WARNING: this configuration may cache passwords in memory -- use the auth-nocache option to prevent this
Wed Jan 13 17:43:48 2016 VERIFY OK: depth=1, C=DE, ST=Berlin, L=Berlin, O=Charite-VPN, OU=GB-IT, CN=Charite-VPN CA, name=EasyRSA, emailAddress=vpn@charite.de
Wed Jan 13 17:43:48 2016 VERIFY OK: nsCertType=SERVER
Wed Jan 13 17:43:48 2016 Validating certificate extended key usage
Wed Jan 13 17:43:48 2016 ++ Certificate has EKU (str) TLS Web Server Authentication, expects TLS Web Server Authentication
Wed Jan 13 17:43:48 2016 VERIFY EKU OK
Wed Jan 13 17:43:48 2016 VERIFY X509NAME OK: C=DE, ST=Berlin, L=Berlin, O=Charite-VPN, OU=GB-IT, CN=openvpn.charite.de, emailAddress=vpn@charite.de
Wed Jan 13 17:43:48 2016 VERIFY OK: depth=0, C=DE, ST=Berlin, L=Berlin, O=Charite-VPN, OU=GB-IT, CN=openvpn.charite.de, emailAddress=vpn@charite.de
Wed Jan 13 17:43:48 2016 Data Channel Encrypt: Cipher 'AES-256-CBC' initialized with 256 bit key
Wed Jan 13 17:43:48 2016 Data Channel Encrypt: Using 256 bit message hash 'SHA256' for HMAC authentication
Wed Jan 13 17:43:48 2016 Data Channel Decrypt: Cipher 'AES-256-CBC' initialized with 256 bit key
Wed Jan 13 17:43:48 2016 Data Channel Decrypt: Using 256 bit message hash 'SHA256' for HMAC authentication
Wed Jan 13 17:43:48 2016 Control Channel: TLSv1.2, cipher TLSv1/SSLv3 ECDHE-RSA-AES256-GCM-SHA384, 2048 bit RSA
Wed Jan 13 17:43:48 2016 [openvpn.charite.de] Peer Connection Initiated with [AF_INET]193.175.73.200:1194
Wed Jan 13 17:43:49 2016 MANAGEMENT: >STATE:1452703429,GET_CONFIG,,,
Wed Jan 13 17:43:50 2016 SENT CONTROL [openvpn.charite.de]: 'PUSH_REQUEST' (status=1)
Wed Jan 13 17:43:50 2016 PUSH: Received control message: 'PUSH_REPLY,dhcp-option DNS 141.42.3.33,dhcp-option DNS 141.42.2.22,dhcp-option DOMAIN charite.de,register-dns,block-outside-dns,route-gateway 172.29.0.1,topology subnet,ping 10,ping-restart 30,redirect-gateway def1,ifconfig 172.29.15.46 255.255.192.0,peer-id 73'
Wed Jan 13 17:43:50 2016 OPTIONS IMPORT: timers and/or timeouts modified
Wed Jan 13 17:43:50 2016 OPTIONS IMPORT: --ifconfig/up options modified
Wed Jan 13 17:43:50 2016 OPTIONS IMPORT: route options modified
Wed Jan 13 17:43:50 2016 OPTIONS IMPORT: route-related options modified
Wed Jan 13 17:43:50 2016 OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified
Wed Jan 13 17:43:50 2016 OPTIONS IMPORT: peer-id set
Wed Jan 13 17:43:50 2016 OPTIONS IMPORT: adjusting link_mtu to 1573
Wed Jan 13 17:43:50 2016 ROUTE_GATEWAY 192.168.2.1/255.255.255.0 I=9 HWADDR=00:1f:3b:52:14:69
Wed Jan 13 17:43:50 2016 do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0
Wed Jan 13 17:43:50 2016 MANAGEMENT: >STATE:1452703430,ASSIGN_IP,,172.29.15.46,
Wed Jan 13 17:43:50 2016 open_tun, tt->ipv6=0
Wed Jan 13 17:43:50 2016 TAP-WIN32 device [LAN-Verbindung 2] opened: \\\\.\\Global\\{EC522D4B-25A4-4A92-84A3-D4A3F459251F}.tap
Wed Jan 13 17:43:50 2016 TAP-Windows Driver Version 9.21 
Wed Jan 13 17:43:50 2016 Set TAP-Windows TUN subnet mode network/local/netmask = 172.29.0.0/172.29.15.46/255.255.192.0 [SUCCEEDED]
Wed Jan 13 17:43:50 2016 Notified TAP-Windows driver to set a DHCP IP/netmask of 172.29.15.46/255.255.192.0 on interface {EC522D4B-25A4-4A92-84A3-D4A3F459251F} [DHCP-serv: 172.29.63.254, lease-time: 31536000]
Wed Jan 13 17:43:50 2016 Successful ARP Flush on interface [15] {EC522D4B-25A4-4A92-84A3-D4A3F459251F}
Wed Jan 13 17:43:50 2016 Can't add WFP filter
Wed Jan 13 17:43:50 2016 MANAGEMENT: Client disconnected
Wed Jan 13 17:43:50 2016 Blocking DNS failed!
Wed Jan 13 17:43:50 2016 Exiting due to fatal error


Is "Can't add WFP filter" the cause for that fatal error?
How can I find out WHY it could not be added?