These errors may be seen if there are any Filters, Property Controls or Dynamic items in the TextArea visualization but have been commented out. For example when you right click on a text area and choose "Edit HTML" you will see below commented out HTML:
<!--<SpotfireControl id="83a089880cda49478e5ebd0d111d81fd" />-->
Though these controls in the TextArea visualization are commented, Spotfire still tries to render these controls but fails as the respective DOM elements are not present and thus causing the error.
To resolve the issue, remove the commented out controls from the TextArea visualization and save the analysis file or upgrade to Spotfire versions 10.4 and higher.