Most likely, ->spawn() does not spawn a shell. If you change your code to first spawn a shell and then run your shell commands, it might work.

As an alternative, setting elements in %ENV also sets the environment for child processes, so you can do that:

$ENV{ CVSROOT }=':pserver:user11@10.x.x.X:/export/DEMO';
...
    $shell_obj = Expect->spawn('echo $CVSROOT') or die "Couldn't start
+ a program: $!\n";
[download]

Note that this only works if echo is an external program and not only a shell builtin.