mcp2 , i missed the line in your earlier post where you said your player plays AMV files. If so, then your player is an Actions chipset.
What version is it currently using?
S1fwx v3.2 would only work with Actions chipsets with firmware v9.0.43 and below. It is very likely that your player might be using a newer version not yet supported.
If your player is working fine, i'll suggest not doing anything to the firmware, like updates and things like that. As usually you'll stand a better chance of bricking it instead.
However, i'll do suggest that you format your player as many 4GB players are usually hacked 1 or 2GB chips. The guide is here
http://www.mympxplayer.org/viewtopic.php?t=2400