This error was probably caused when Unicode characters were pasted from Word. The dictionary lexicons accept only ASCII characters.
You'll need to start with a fresh copy of the user dictionary and add the following regualr expressions to the spell() function to convert common Unicode characters found in Word content.
<script>
function spell()
{
var currentContent = eval("document.myForm.content.value");
currentContent = currentContent.replace(//g, "-"); //8211
currentContent = currentContent.replace(//g, "'"); //8216
currentContent = currentContent.replace(//g, "'"); //8217
currentContent = currentContent.replace(//g, '"'); //8220
currentContent = currentContent.replace(//g, '"'); //8221
window.open("/support/kb/indexcfm/fuseaction/single/id/1062/window_jsvar_document.myForm.content.value.html",null, "height=230,width=450,status=no,toolbar=no,menubar=no,location=no");
}
</script>