WORKAROUND #1:
Divide these ALTER TABLE statements into two separate statements. The first adds a new column and the second creates a primary key.
WORKAROUND #2:
Execute the original DDL script in the database and then reverse engineer the created result.
STATUS:
This issue is fixed in Toad Data Modeler 6.1. This version can be downloaded from the downloads section of our website, which you can access by clicking
here.