S-FTP HP-UX to Bitvise (Win NT)

Trying to connect to an HP-UX machine using public key authentication - using User keypair manager to create a keypair - export the public key to a file - tried both OpenSSH and SSH2 - and then transfer the public key to the $HOME/.ssh/authorized_keys file on the Unix box - but when I try to connect it fails to make the connect - see log below. I have transferred the file in both binary and ascii format using normal FTP - (don't know if that is wrong or not) It does initial connection - but then refuses the key for some reason.
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Any ideas someone please ??

Thanks

Log is:

10:24:24.371 Bitvise Tunnelier, a fully featured SSH2 client.
Copyright � 2000-2005 by Bitvise Limited.
Portions Copyright � 1995-2003 by Wei Dai.
10:24:24.371 Visit www.bitvise.com for latest information about our SSH2 products.
10:24:24.371 Run 'Tunnelier -help' to learn the supported command-line parameters.
10:24:24.576 Loading default profile.
10:24:37.356 Starting a new SSH2 session.
10:24:37.372 Connecting to SSH2 server c-eurs01.eu.jci.com:22.
10:24:37.718 Connected.
10:24:37.750 Starting first key exchange.
10:24:41.248 Server version string: SSH-1.99-OpenSSH_3.9p1
10:24:41.894 New host key received. Algorithm: ssh-rsa, Size: 1024 bits, MD5 Fingerprint: a3:32:13:82:f7:13:78:35:fc:29:6a:68:2e:ba:94:a0, Bubble-Babble: xivoz-zilaz-vesur-higif-vydyg-bopok-vynun-bapys-nyvob-hikal-boxux.
10:24:41.910 First key exchange completed.
10:24:41.910 Key exchange: diffie-hellman-group14-sha1. Session encryption: aes256-cbc, MAC: hmac-sha1, compression: none.
10:24:41.973 Attempting 'publickey' authentication. Using keypair at slot 1.
10:24:42.257 Authentication failed. Remaining authentication methods: 'publickey,password,keyboard-interactive'.
10:24:52.216 Session terminated on user's request.
10:25:34.827 The current initial authentication is no longer available. Switching to none.
10:26:47.774 Starting a new SSH2 session.
10:26:47.790 Connecting to SSH2 server c-eurs01.eu.jci.com:22.
10:26:47.869 Connected.
10:26:47.884 Starting first key exchange.
10:26:51.367 Server version string: SSH-1.99-OpenSSH_3.9p1
10:26:51.966 New host key received. Algorithm: ssh-rsa, Size: 1024 bits, MD5 Fingerprint: a3:32:13:82:f7:13:78:35:fc:29:6a:68:2e:ba:94:a0, Bubble-Babble: xivoz-zilaz-vesur-higif-vydyg-bopok-vynun-bapys-nyvob-hikal-boxux.
10:26:51.997 First key exchange completed.
10:26:52.013 Key exchange: diffie-hellman-group14-sha1. Session encryption: aes256-cbc, MAC: hmac-sha1, compression: none.
10:26:52.123 Attempting 'none' authentication.
10:26:52.391 User authentication banner received from the server.
10:26:56.252 Authentication failed. Remaining authentication methods: 'publickey,password,keyboard-interactive'.
10:27:10.892 Attempting 'publickey' authentication. Testing keypair slot 1 for acceptance.
10:27:10.955 Authentication failed. The keypair has been rejected. Remaining authentication methods: 'publickey,password,keyboard-interactive'.
10:27:16.738 Session terminated on user's request.
10:27:39.052 Starting a new SSH2 session.
10:27:39.068 Connecting to SSH2 server c-eurs01.eu.jci.com:22.
10:27:39.163 Connected.
10:27:39.179 Starting first key exchange.
10:27:42.645 Server version string: SSH-1.99-OpenSSH_3.9p1
10:27:43.323 New host key received. Algorithm: ssh-rsa, Size: 1024 bits, MD5 Fingerprint: a3:32:13:82:f7:13:78:35:fc:29:6a:68:2e:ba:94:a0, Bubble-Babble: xivoz-zilaz-vesur-higif-vydyg-bopok-vynun-bapys-nyvob-hikal-boxux.
10:27:43.355 First key exchange completed.
10:27:43.370 Key exchange: diffie-hellman-group14-sha1. Session encryption: aes256-cbc, MAC: hmac-sha1, compression: none.
10:27:43.449 Attempting 'none' authentication.
10:27:43.764 User authentication banner received from the server.
10:27:45.214 Authentication failed. Remaining authentication methods: 'publickey,password,keyboard-interactive'.
10:27:50.068 Attempting 'publickey' authentication. Testing keypair slot 1 for acceptance.
10:27:50.147 Authentication failed. The keypair has been rejected. Remaining authentication methods: 'publickey,password,keyboard-interactive'.
10:27:53.755 Session terminated on user's request.
10:28:02.769 Copying log to clipboard succeeded.

I am using the OpenSSH format - I actually tried both - and the permissions on the Unix side are correctly set at 600 for the file.

Thanks for the response