Failed to determine type of private key

[lnp at healy.washington.dc.us (Liam Healy)]

I am trying to write a script to connect to a server which I can
successfully connect to using the Network Manager interface to
OpenConnect. My script is:

 NAME="myusername"
      GROUP="MYGROUP"
      PIDFILE="openconnect.pid"
      CERT="/etc/ssl/certs/servercert.pem"
      HOST="https://vpn.example.com";
      SCRIPT="/etc/vpnc/vpnc-script"

      openconnect -b -c $CERT --script $SCRIPT --pid-file=$PIDFILE
--user=$NAME --usergroup=$GROUP

What I expect when I run this from the shell is that I will be
prompted for my password and then I will connect to the server, as
happens when run from network manager. What I get is:

 POST https://vpn.example.com/MYGROUP
      Attempting to connect to server 1.1.1.4:443
      Failed to determine type of private key /etc/ssl/certs/servercert.pem
      Loading certificate failed. Aborting.
      Failed to open HTTPS connection to vpn.example.com
      GET https://vpn.example.com/MYGROUP
      Attempting to connect to server 1.1.1.6:443
      Failed to determine type of private key /etc/ssl/certs/servercert.pem
      Loading certificate failed. Aborting.
      Failed to open HTTPS connection to vpn.example.com
      Failed to obtain WebVPN cookie

and no connection. On nm, I do get a message "SSL certificate
authentication failed", but it connects.

My questions: How do I connect to the VPN from the command line? How
do I remove the message about the certificate authentication when
using nm? Is it possible to find out the command-line equivalent of
what nm is doing?

Ubuntu 14.04LTS
OpenConnect version v5.02
Using GnuTLS. Features present: PKCS#11, TOTP software token, DTLS
(using OpenSSL)
Linux 3.13.0-39-generic #66-Ubuntu SMP Tue Oct 28 13:30:27 UTC 2014
x86_64 x86_64 x86_64 GNU/Linux


Thank you,
Liam