Same Domain – New Server Export & Import Danger?

[ Moved to the Fixing WordPress sub-forum. ]

So this is the first time I’ve run into a site that I couldn’t transfer with the good old fashioned FTP+PHP export>import method.

There’s something really wrong with the database, and I don’t think anyone wants to pay to fix it. So we’re building a new site. Same Domain, new host, using the edit “hosts” file trick to view the new site on the new server until the process is complete.

Here’s the problem:

I plan to use the export function for the posts and then the media. However, I am afraid of the import function. When I export the posts and use the import function with the “Download and import file attachments” box checked the attachments don’t import.

So my next thought is, I should use the export media function. If I do this export media function and then import the media XML with the “Download and import file attachments” box checked, will it harm the files on the current site?

I did this with one post but did not check first if the media/images showed up on the original site. However afterward they definitely did not. So I am rather worried.