Can anyone please tell me what is Rcx?
On the SFP 3.1c update page, theres a note saying: "IMPORTANT: The version SFP 3.1a, SFP 3.1b or SFP v3.1c - RCx must already be installed."
In fact: "IMPORTANT: The version SFP 3.1a, SFP 3.1b or SFP v3.1c - RCx must already be installed. Please download the update patch." RCx is Release Candidate and x is a number (2,3) - it's the same like they write Win9x instead of writing Win95&98. Release candidate x was a version of SFP after the 3.a,b but before the full 3.1c and is no longer available (what for?) so don't bother it.