Open VPN site to site not working, but laptop connection does

[thetallkid]

I have an pfsense running snapshot 2.1 and a remote laptop can connect, have access to all of the machines and services behind the firewall. So I know that openvpn works, has been for close to a year.

I recently set up a remote pfsense alix box running 2.0.1 and I attempted to setup a site to site vpn network between the two following the excellent tutorials here. It didn't connect. Checked the logs on the main firewall and got the following error:

openvpn[13086]: Authenticate/Decrypt packet error: packet HMAC authentication failed
                        openvpn[13086]: TLS Error: incoming packet authentication failed from [AF_INET]71.xx.xx.xx:41685

I re-exported the CA cert, server cert and key, made sure that they were labelled correctly before importing them into the remote firewall. Double checked that the tunnel subnets matched and that routes also matched.
This is the error message from the logs on the client side:

openvpn[16958]: WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info.
                      openvpn[16958]: NOTE: the current –script-security setting may allow this configuration to call user-defined scripts
                      openvpn[16958]: Re-using SSL/TLS context

Did the usual google search and checked the posts here but could not find a solution. Played around with the settings but can't figure out where I have gone wrong. Any help is appreciated.

[BSV]

Does it help if you run the openvpn client as administrator? (right click on VPN shortcut and then run as administrator)