The remote control codes are compatible with all Slingplayer versions. There ARE different bin files required depending on the version of the IR chipset used in the Slingbox (JU, PL and RV types). Perhaps this is your concern? I strongly suspect that there will be a way to get it working on your classic.
Also you can update to the newer 2.0.4.522 version of Slingplayer if you wish. The newer versions have a strong desire to for you have an account with SlingMedia, but if you plan to use it for local viewing it is not required. I generally have both versions installed.
The classic Slingbox can no longer be used with the web browser based players. They are also no longer supported on but still work with iPhone and BlackBerry apps. I think that I recall some limitation with the Mac app (needing to log in as admin instead of view only and no HD resolution for PRO HD).