Import Issues

I’m moving my GD information from one website to another, already existing, website. Here’s the issues I’m running into:

1) I exported the .csv files from GD on the original website, but when I try to import them into the new destination the gd_locations_xxxxxxxxxxx.csv and gd_placecategory_xxxxxxxxxx.csv files won’t import. I get an error message saying that they’re not a valid .csv file.
2) When I tried importing the gd_place_xxxxxxxxxxxx.csv file, not all the records import. It says that there’s already posts with identical post id’s (which, considering this isn’t a brand new site I’m importing into, seems likely). How do I import the existing data into the new site without stepping on existing post id’s?

I have installed all the same GD add-ons on the new site as exist on the old site. Any suggestions?

Thanks,
Greg