Yes, it is an SSH connection. Still, apparently the client you're using is not providing a proper full-screen emulation as it should.
Try
Putty for a change.
If you're connecting through LISH emergency console (
linodeXXXXX@datacenterXX.linode.com), make sure to set your program's window size to 80x24, and type
Code:
TERM=vt100
export TERM
after login and before the call to dpkg-reconfigure.
If you're using a regular connection to your sshd (yourlogin@yourlinodeaddress) it should not be necessary.
In any case, you can try falling back to Debconf's text interface, which has a better chance of working in a misconfigured terminal:
Code:
dpkg-reconfigure -freadline tzdata