TinyMCE with WYSIWYG stops working in IE8 when js is paralleled

TinyMCE via WYSIWYG module will not load in IE8 when javascripts are paralleled. . .

I've tried with both the latest dev and with beta2 and the prob is the same.

Firefox works fine IE8 doesn't (no surprises there).

IE gives the following. . .

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; WOW64; Trident/4.0; hc; SLCC1; .NET CLR 2.0.50727; InfoPath.2; .NET CLR 3.5.30729; .NET CLR 3.0.30729; OfficeLiveConnector.1.5; OfficeLivePatch.1.3; .NET4.0C; AskTB5.6)
Timestamp: Fri, 15 Oct 2010 14:23:05 UTC


Message: Access is denied.

Line: 1
Char: 9950
Code: 0
URI: http://js.xyz.co.uk/sites/all/libraries/tinymce/jscripts/tiny_mce/tiny_mce.js?g

I've listed this as a support request since I'm sure the problem is with IE8, rather than a 'bug' in parallel.module.
Can anyone help me out with a workaround?

Thanks in advance. . .