Firefox is looking for a file named places.sqlite (in case your file is really named places.sql).

Where did you paste the file? You need to replace the one in your currently active profile folder. You probably can judge by the time stamps, but you also can use the steps in this article to access the live folder: Profiles - Where Firefox stores your bookmarks, passwords and other user data. (Naturally, Firefox should be fully shut down before replacing that file.)

If you can't get a places.sqlite transplant to take, consider restoring bookmark backup files from your old system. They would be located in a folder named bookmarkbackups in your old profile folder. You can drop them in the corresponding folder in your new Firefox profile, then use the steps in this article: Restore bookmarks from backup or move them to another computer.

Regarding the user interface, many aspects can be modified, but you'll need to get very specific if you want suggestions on how to do it. Do you want to pursue that in this thread or start a new one?

I gave up on the places.sqlite transfer since it didn't work regardless of how it was done. I finally replaced the entire profile with the old version, and I renamed it the same as the current profile after changing the file type on the current profile to .old. That worked.

As for the user interface, there's just no good justification for it, and the icon based controls, especially when they are not consistent, are just one more aggravation in a long line by software providers. I'm dying for the day when a 'windows like' operating system is introduced that guarantees no changes to the interface and includes a browser and an email client server with the purchase. It'll put MS clean out of business.