looks lioke there is a bug in the CKEdiot 4.0 version that Data Bridge uses that causes the Spell Checker to fail.
you can update the CKEditor Files manually to a newer version that has this bug fixed.
in the webassist/ folder, rename the ckeditor folder to ckeditor_bak
On this page:
click the button to launch CK Builder. Select to use the Full Preset, and the Kama Skin.
Copy the downloaded CKEditor folder to the webassist folder in your site.
from the ckeditor_back folder, copy the following three files:
and paste them in the new ckeditor folder.
you will need to clear the browsers cache to see the updates take effect.
I have logged a bug in our system so the data Bridge CKEditor version should be updated in the next release.