Your Else and ElseIf tests are identical. Are you sure this is what you want?
Not sure. I want the script to copy the contents of the field if there are any and stop, or do something else, if not.
Why is To Do List in a different file? If you put all your tables in one file, life is much simpler.
With the tables in separate files, you can define an external data source reference to the other table and then a single script in one file can move the data from one table to another. But this may not be needed at all if I recall your other post correctly.
The Copy script step creates problems for your users as it copies data to the system clipboard. If the user has copied data to the clipboard before performing this script, they will not be happy to discover that their copied data has been replaced by data copied by this script.
Copy will silently fail to copy any data if the layout that is "current" at the time the script step executes does not have the specified field and it is not accessible in Browse mode.
Set Variable can be used in place of Copy and Set field can be used in place of Paste to avoid using copy/paste when the entire script is performed in a single file. If you want to pass this data to a script in another file, you can pass this data as a script parameter and still avoid copy/paste as a way to move data from one table to another.