I cannot seem to import a WXR file into my new Worpdress (advanced) install that I recently set up on DH. I moved from another host and exported a 10.6 MB file. I tired splitting it up into 1.2 MB chucks.
What happens is when I press the “Upload File and import button”, wordpress is forever stuck on contacting the host. but the import never goes through.
If WP is using PHP as it’s upload function you’ll have to raise the default size (7mb) via php.ini
Check your upload settings via Admin.
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I’ve kept modfied the WXR file to be only a few MB and I still have this problem. What admin menu are you suggesting? The dreamhost cp or the wordpress settings somewhere?
WordPress Admin. I’m not a WP user so couldn’t direct you further with Admin but I’m sure someone here who does will be able to point you in the right direction 
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As I look at a WXR file from my test site, it’s not something I’d try to split up. Seeing how your exported file is 10 megs, you may have to go with the modified php.ini, which really isn’t that much of a challenge.
Out of curiosity, is your blog one author, which limits your ability to export a little at a time? As a test, you could try creating another author with one post and then exporting that author’s content then import it to the new site.
-Scott