What exactly is happening? The only thing I can see is that you put a \ in front of S and P. These aren't special characters, so I don't see why you would need the \.Here is the code without the \ in front of the S and P:
//Start Replacement Scripts.//bodyHlder=document.body;imgRepfir='<img src="http://www.planetsmilies.com/smilies/happy/happy0069.gif" />'finRepf=bodyHlder.innerHTML.replace(/\:\)/g,imgRepfir);bodyHlder.innerHTML=finRepf;imgRepsec='<img src="http://www.planetsmilies.com/smilies/confused/confused0069.gif" />'finRepg=bodyHlder.innerHTML.replace(/\:S/g,imgRepsec);bodyHlder.innerHTML=finRepg;bodyHlder=document.body;imgRepthi='<img src="http://www.planetsmilies.com/smilies/sad/sad0119.gif" />'finReph=bodyHlder.innerHTML.replace(/\:\(/g,imgRepthi);bodyHlder.innerHTML=finReph;bodyHlder=document.body;imgRepfo='<img src="http://www.planetsmilies.com/smilies/tongue/tongue0021.gif" />'finRepj=bodyHlder.innerHTML.replace(/\:P/g,imgRepfo);bodyHlder.innerHTML=finRepj;bodyHlder=document.body;imgRepfi='<img src="http://www.planetsmilies.com/smilies/winking/winking0001.gif" />'finRepk=bodyHlder.innerHTML.replace(/\;\)/g,imgRepfi);bodyHlder.innerHTML=finRepk;///End Replacement Scripts///
Let me know if that works.