Whats wrong with this javascript

For some reason this javascript gives a java error on my showthread.php

<script language="javascript" type="text/javascript">
<!--
function aimwindow(aimid) {
	window.open("member.php?s=$session[sessionhash]&action=aimmessage&aim=" aimid","_blank","toolbar=no,location=no,menubar=no,scrollbars=no,width=175,height=275,resizeable=yes,status=no")
}
// -->
</script>

To my knowledge it hasn't been edited in anyway.

can someone tell me whats wrong with it


thanks in advanced

[Scott MacVicar]

<script language="javascript" type="text/javascript">
<!--
function aimwindow(aimid) {
	window.open("member.php?s=&action=aimmessage&aim="+aimid,"_blank","toolbar=no,location=no,menubar=no,scrollbars=no,width=175,height=275,resizeable=yes,status=no")
}
// -->
</script>

you had aim=" aimid",

that should hav ebeen
aim="+aimid,

use code posted above.