Getting error "Invalid data type 'CDATA'." when trying to save a model
The model contains control characters than cannot be saved as xml.
Adding a char between these chars can help.
WORKAROUND 1
Save the model as binary
WORKAROUND 2
Add a space between the chars. For example replace

WORKAROUND 3
Comment the problematic code
STATUS
Issue fixed in version 6.5. The latest version of Toad Data Modeler can be downloaded here .