HTML import button of tasks uses predecessors numbers not in the database

The native method of creating child records will preserve the predecessors properly.

You have not described your use case,  but have you explored the functionality in app management for the wizard which is titled Copy Master Detail?

A typical use for that is that you have a a situation where you have say 6 standard Projects each with its own set of standard tasks.  You would then create 6 buttons to import a set of standard tasks and presented which buttons are presented to the users based on either the user's choice or the "Project Type".

No I have not tried that where is the wizard?

Oh got it I'm looking at it now thank you.

.. and typically, you do a summary count of the # of tasks and then suppress the import std tasks button(s) if the project already has tasks, so that you users don't import the set of tasks in duplicate / triplicate.

So far so good.  With this method, is there a way to "import" the copy button from one table to another?  In other words, can I have multiple buttons on a projects, one which imports table x, one which imports table y, and on for z?

I don't know what you mean by import a button.  The button can be created using the API method, or by using that Wizard to build the button for you, or if you understand what the parameters of the button code are, you can copy that button  and edit it's parameters to save time building multiple button with the wizard..

Well then let me say Mazel Tov on your journey. :)

Yup...  So far. so good.

I'm trying to copy a specific project, and when I hit the "copy" button, I receive the following:  There was an error copying the records. Contact the application administrator with the error details below. 

Error Details:
CopyFID required