back end error index was outside the bounds of the array when tinymce is loading

Hi,
I've just encountered this problem with one of my Umbraco sites, and its only happening on one page. The page has been fine for about a week since the site went live, but I just saved & published the page and now when ever I click on the page in Umbraco I get the error below and I can't edit the page. The page still loads fine on the live site, its just in the back-end where the problem is occurring. Has anybody seen this sort of error before? Looks like something to do with the tinymce attempting to load the content?

Umbraco 4.1, VPS is Windows 2000 Server with IIS 6

Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 2/5/2010 5:01:39 PM
Event time (UTC): 2/5/2010 6:01:39 AM
Event ID: b911d73ccd61412ebb3a555d89895d2f
Event sequence: 160
Event occurrence: 2
Event detail code: 0
 
Application information:
    Application domain: /LM/W3SVC/1232665169/Root-1-129098225006532500
    Trust level: Full
    Application Virtual Path: /
    Machine name: CT2789
 
Process information:
    Process ID: 182328
    Process name: w3wp.exe
    Account name: NT AUTHORITY\NETWORK SERVICE
 
Exception information:
    Exception type: IndexOutOfRangeException
    Exception message: Index was outside the bounds of the array.
 
Request information:
    Request URL: www.domain.com.au/umbraco/editContent.aspx?id=1052
    Request path: /umbraco/editContent.aspx
    User host address: removed from this post
    User: 
    Is authenticated: False
    Authentication Type: 
    Thread account name: NT AUTHORITY\NETWORK SERVICE
 
Thread information:
    Thread ID: 9
    Thread account name: NT AUTHORITY\NETWORK SERVICE
    Is impersonating: False
    Stack trace:    at umbraco.editorControls.tinyMCE3.webcontrol.TinyMCEWebControl.getIdFromSource(String src, String localMediaPath)
   at umbraco.editorControls.tinyMCE3.webcontrol.TinyMCEWebControl.formatMedia(String html)
   at umbraco.editorControls.tinyMCE3.webcontrol.TinyMCEWebControl.OnPreRender(EventArgs e)
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Control.PreRenderRecursiveInternal()
   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)