I'm trying to get the TinyMCE spell checker to work on my site. Apart from enabling the spell checker feature in the Richtext editor data type, I'm guessing that I have to uncomment the config line in tinyMceConfig.config and add my own Google API key there ?

<!--
 
 this area is for custom config settings that should be added during TinyMCE initialization -->
<
 
customConfig>
<
 
config key="myKey">ABQIAArAKxZh7jsk9cUQJnqf8dMnzhQuffq7q63jGKVha4MF9TSieInY9RRo0mbaVLP8frzwmC1BVhHoCPLEnQ</config>
<
 
config key="entity_encoding">raw</config>
<
 
config key="spellchecker_rpc_url">GoogleSpellChecker.ashx</config>
</
 
customConfig> 

After I've recycled the app pool (to ensure that it re-reads the config) I'm getting an error when hitting the spell check button in the TinyCME editor:

Index and length must refer to a location within the string

Am I missing some steps here or am I on a wrong track of some sorts? :P