Customer to Enter Shipping Amount

[Checkit]

I'm trying to set up the shipping system in the Checkout, so that local customers can select from three flat rate options $2 $5 or $10, and international customers can enter the amount (as per the amount in the item description) in an empty field.

I've read about copying and renaming the flat.php file, so I could have flat1.php, flat2.php, unfortunately I seem to get stuck, when I click on copy file in my control panel, it asks me where I want to save the file, and then won't let me save it.

A request total option in checkout for customers who are unsure of the total would also be really useful.

As to the first part, if someone can suggest how I can complete the copy part of the process, I should be able to do the rest, changing all the flat to flat1, FLAT to FLAT1, and the same in the associated languages/english/modules/shipping/flat.php files.

Yesterday I didn't know what PHP was, so a simple explanation might be better.

Thanks

[Checkit]

Well, I worked out how to create a new file, copy the script from the old file, rename all the flat to flat1 etc, but kept getting warning messages when I checked it in the ZC admin. There was a new flat1 module there to be installed, but I wasn't game with all the error in line 174 messages everywhere.
Can anyone tell me what my error in line 174 was?

[Checkit]

Despite being reasonably adequate at following instructions, I continue to get warning and error messages in admin after I create new flat.php files for the shipping module.
Who else wishes they had actually just paid for a program that works?

[Ajeh]

Usually this is due to typos of mismatched case on the global replaces of flat with flatuk or FLATUK ...

Or perhaps you included an underscore such as flat_uk which would run into a conflict with flat ...

The modules need to "own" their own variables and filenames exclusively ...

These conflicts can show up in the catalog or the admin ...

[Ajeh]

NOTE: there are also 109 lines to flat.php ...