DB2 will not INSERT into Created Temp Table that I created
By default the global temporary tables are created with the option ON COMMIT DELETE ROWS. Whatever tool you are using to run your statements must have the autocommit option turned on, so as soon as you issue the INSERT statement it is committed, thus deleting rows in the table.

You should either create the table using the ON COMMIT PRESERVE ROWS option, or disable autocommit while running your commands and issue an explicit COMMIT when you are done. Which option you choose depends on your business logic.