what version of mojoPortal? we shipped a new release yesterday
what version did you upgrade from?
Sounds like you are saying that the editor is failing to load, you should use the web browser dev tools to look for script errors in the console and look for any script or css files that fail to load in the network tab.
Make sure in Site Settings that you are using either CKeditor or TinyMCE, click the save button to make sure.
Also if you upgraded you should review the Important Skin Changes, if using an older Artisteer skin you may need to enable the jquery migrate plugin as mentioned there.