Impossible to add a webpart to a Gantt view of a list

I am a sharepoint user without access to sharepoint designer. I'm hoping to create a Gantt chart with a modified timescale, as per http://blog.pathtosharepoint.com/2008/11/08/how-to-scale-down-the-sharepoint-gantt-view/, i.e. add a Custom Editor Web Part with some css in it which changes the timescale.

The steps I take are

1. Create a new Custom List (also tried this with Tasks or "Project tasks"
2. Create a new view for that list and choose type "Gantt"
3. Site Actions => Edit Page => Add Web part => Content Editor Web Part
4. At this stage I get an error message

Unable to add selected web part(s). Content Editor Web Part : Exception occurred. (Exception from HRESULT: 0x80020009 (DISP_E_EXCEPTION))

It's a bit frustrating to have the solution to the display issue, to see that the entire planet seems to use it quite happily, and to be unable to implement it on our installation.

Best regards,

Colm

• First create the Gantt view,
• then include this as a webpart in a separate wiki-page
• then add a CEWP to this separate wiki-page

Now you can do as indicated in the linked article above.