How many SP/ARWL's do you have setup? Did you hack it to run TiVoWeb, mfs_ftp, telnet, etc....? If yes do you start anything besides telnet at startup? When was the last time you restarted it? I'm sure you've changed the batteries on the remote.

I know that the Phillips units have two different remotes one that is 16bit and one that is 32bit. The 32bit acts like what your describing, you don't have two different units in the same house do you?