unfortunatly i cannot seem to connect to the mirror of the math/crypto part to download it, but after looking over the documentation and having played a bit with Expect and Net::Telnet I think that you may want to check and make sure the following options are working correctly..... sorry i cannot be of more help.

Looks like it might help: use_pty = 1

From the doc :

$ssh->shell

Opens up an interactive shell on the remote machine and connects it to your STDIN. This is most effective when used with a pseudo tty; otherwise you won't get a command line prompt, and it won't look much like a shell. For this reason--unless you've specifically declined one--a pty will be requested from the remote machine, even if you haven't set the use_pty argument to new (described above). This is really only useful in an interactive program. In addition, you'll probably want to set your terminal to raw input before calling this method. This lets Net::SSH::Perl process each character and send it off to the remote machine, as you type it.

There may be some use for this dispite a lack of interactivity... sometimes a program wants to send stuff in an 'interactive' way even though it isnt interactive

sorry i cant seem to install this to play around with it.