I believe I found the bug with SSL connections to the IMAP server in v0.1-20051007.
On line 77 in rcube_imap.inc: global $ICL_PORT, $CONFIG; needs to be changed to: global $ICL_SSL, $ICL_PORT, $CONFIG;
$ICL_SSL was not declared global in the the connect funciton, so that the iil_Connect method would see ICL_SSL as being empty, and never use SSL encryption (somewhere along the line, this would cause an issue and roundcube would never actually connect to the imap server at all).
Changing that line caused it to work for me.
Rob