when using session.use_trans_sid and the client does not allow cookies the javascript code of the page is changed.
example:

normal code:
<!--
function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x=a[i])&&x.oSrc;i++) x.src=x.oSrc;
}
...
//-->

code when parsed with SID:
<!--
function MM_swapImgRestore() { //v3.0
  var i,x,a=document.MM_sr; for(i=0;a&&i<a.length&&(x="a[i])&&x.oSrc;i++)" x.src="x.oSrc;
"
}
//-->

ok, you see that four "s where added!
so the javascript is useless and the page causes an error.

greetings,

steve