[TYPO3] Problems loading Htmlarea in 4.0.2

[Thomas Rune Korsgaard]

Hello

I've just upgraded a site from 3.6 to 4.0.2, but there seems to be a
problem with the htmlArea extention (1.4.2). When I access a text
content element, the editor starts to load, but it stalls with "The
editor is being loaded. Please wait...". If I turn on troubleshooting
I get the following error repeating it self all the time:

[HTMLArea::initIframe]: Failed attempt at loading stylesheets:
[Exception... "A parameter or an operation is not supported by the
underlying object" code: "15" nsresult: "0x8053000f
(NS_ERROR_DOM_INVALID_ACCESS_ERR)" location:
"http://xxxxxxxxxxxxxxxxxx/typo3temp/rtehtmlarea_htmlarea_0915bd0be4db5659ab57c2b44ca50136.js
Line: 1010"] Retrying...

Can anybody help me on this one?

Yours,
/Thomas