"Internal Server Error" on https://<ip-address>:8000

I installed Ajenti on CentOS 6.4 64bit as instructed, but I can't login or even get a login screen. All I get is a white page with "Internal Server Error".

When I start with "ajenti-panel -v" in ssh it all looks ok except for the following error:

"ERROR SSL tunnel failed to start"

I got a same issue as a previous issue filed here: http://ajenti.userecho.com/topic/202435-this-webpage-is-not-available

Below the full log of running it with the stunnel test provided by Eugeny (https://gist.github.com/Eugeny/6038158).

[root@dappervps1 ~]# stunnel /tmp/stunnel.conf
2013.08.04 21:07:28 LOG5[1199:140560269387712]: stunnel 4.29 on x86_64-redhat-linux-gnu with OpenSSL 1.0.0-fips 29 Mar 2010
2013.08.04 21:07:28 LOG5[1199:140560269387712]: Threading:PTHREAD SSL:ENGINE Sockets:POLL,IPv6 Auth:LIBWRAP
2013.08.04 21:07:28 LOG5[1199:140560269387712]: 500 clients allowed
2013.08.04 21:07:37 LOG5[1199:140560269383424]: default accepted connection from 12.34.56.789:52507
2013.08.04 21:07:37 LOG5[1199:140560269383424]: connect_blocking: connected 127.0.0.1:8000
2013.08.04 21:07:37 LOG5[1199:140560269383424]: default connected remote server from 127.0.0.1:35719
2013.08.04 21:07:37 LOG5[1199:140560269383424]: Connection closed: 0 bytes sent to SSL, 0 bytes sent to socket
2013.08.04 21:07:37 LOG5[1199:140560269383424]: default accepted connection from 12.34.56.789:52506
2013.08.04 21:07:37 LOG5[1199:140560269383424]: connect_blocking: connected 127.0.0.1:8000
2013.08.04 21:07:37 LOG5[1199:140560269383424]: default connected remote server from 127.0.0.1:35720
2013.08.04 21:07:37 LOG5[1199:140560269383424]: Connection closed: 0 bytes sent to SSL, 0 bytes sent to socket
2013.08.04 21:07:37 LOG5[1199:140560269383424]: default accepted connection from 12.34.56.789:52509
2013.08.04 21:07:37 LOG5[1199:140560269383424]: connect_blocking: connected 127.0.0.1:8000
2013.08.04 21:07:37 LOG5[1199:140560269383424]: default connected remote server from 127.0.0.1:35721
2013.08.04 21:07:37 LOG5[1199:140560269383424]: Connection closed: 0 bytes sent to SSL, 0 bytes sent to socket
2013.08.04 21:07:37 LOG5[1199:140560269383424]: default accepted connection from 12.34.56.789:52508
2013.08.04 21:07:37 LOG5[1199:140560269383424]: connect_blocking: connected 127.0.0.1:8000
2013.08.04 21:07:37 LOG5[1199:140560269383424]: default connected remote server from 127.0.0.1:35722
2013.08.04 21:07:37 LOG5[1199:140560269383424]: Connection closed: 0 bytes sent to SSL, 0 bytes sent to socket
2013.08.04 21:07:39 LOG5[1199:140560269383424]: default accepted connection from 12.34.56.789:52510
2013.08.04 21:07:39 LOG5[1199:140560269383424]: connect_blocking: connected 127.0.0.1:8000
2013.08.04 21:07:39 LOG5[1199:140560269383424]: default connected remote server from 127.0.0.1:35723
2013.08.04 21:07:40 LOG5[1199:140560269383424]: Connection closed: 161 bytes sent to SSL, 469 bytes sent to socket
2013.08.04 21:07:40 LOG5[1199:140560269383424]: default accepted connection from 12.34.56.789:52511
2013.08.04 21:07:40 LOG5[1199:140560269383424]: connect_blocking: connected 127.0.0.1:8000
2013.08.04 21:07:40 LOG5[1199:140560269383424]: default connected remote server from 127.0.0.1:35724
2013.08.04 21:07:40 LOG5[1199:140560269383424]: Connection closed: 0 bytes sent to SSL, 0 bytes sent to socket
2013.08.04 21:07:40 LOG5[1199:140560269383424]: default accepted connection from 12.34.56.789:52512
2013.08.04 21:07:40 LOG5[1199:140560269383424]: connect_blocking: connected 127.0.0.1:8000
2013.08.04 21:07:40 LOG5[1199:140560269383424]: default connected remote server from 127.0.0.1:35725
2013.08.04 21:07:40 LOG5[1199:140560269383424]: Connection closed: 161 bytes sent to SSL, 420 bytes sent to socket