If you are trying to edit a page on a MS Sharepoint site and clicking the “Edit Content” link yeilds a pop-up window that gives you this message: “cannot open the rich text editor”, there are two workarounds that may fix this.
First, try unregistering and re-registering the control dlls. Open a command prompt and type the following:
> cd C:\Program Files\Common Files\Microsoft Shared\Triedit
> regsvr32 /u dhtmled.ocx
> regsvr32 /u triedit.dll
> regsvr32 dhtmled.ocx
> regsvr32 triedit.dll
Then restart IE. If this doesn’t work, you can try adding the Sharepoint site to your list of trusted sites:
In IE, click Tools>Internet Options>Security Tab>Trusted Sites>Sites Button>Add
Be sure to uncheck the “Require server verification (https:) for all sites in this zone” checkbox if your site does not support SSL.