Do you have a link to where this can be seen at all? There may be a whole page editor option enabled for the editor that is giving the message.
As a test to see if it has to do with the configuration that one is using over the other look in the source code at the iRite instances. The second to the last value of the instance should be the path to the custom config. Mine is called test and looks like this:
$WARichTextEditor_1 = CreateRichTextEditor ("test", "WA_iRite/", "100%", "200px", "Default", "../custom/test_test1.js", "");
In this example it is the ../custom/test_test1.js that is the path to the custom config. Try copying the code for both to a temporary file for safe keeping, then update the first instances custom config path to be like the second, then test the pages. Please let us know what you experience when you switch up the configs on these.