I did not have to replace any code when working with my installation. Our OpenCart and zip versions are the same, and it worked correctly when simply running the install. I'm happy to answer your questions however.
1) Do I FTP the vQmod and export extention files to the Public_html directory or the ROOT directory, there is a listing for EACH of these in my file manager account. I put them in Public.
- You want to put them in the root folder for your OpenCart. If you are using opencart as your site, then it would simply be the public_html folder. If you had OpenCart in a subfolder, say /store, then you would upload to the public_html/store folder.
2) I am using SMART FTP, When I FTP the files, do I drag the top level file with the sub files in it or should drag each sub file separately. I did the top level file and they all seemed to copy.
- I opened the top level folder and then dragged each individual folder over.
3) Should I install the override engine?
- I did not have to do so.
4) If I install the engine, can I just re-FTP the export tool files or do I need to delete the old ones first?
- You can re-FTP, just make sure it is overwriting the ones that are already present.
Not being able to duplicate it on our side makes it hard to give any actionable advice. I hope some of this helps. One final question, have you tried to do a fresh install to a subfolder,then install the vqmod and then the export/import to see if it works? If so, this may indicate some other configuration, plugin, etc that could be interfering.