I moved a couple of WordPress blogs to different domains on the same server, but I made new databases with new hosts on the new domains, rather than uploading the old database to a new home.
I backed up the old databases (there’s more than one set of nice clear instructions somewhere here, Search will turn them up).
Then I opened the database backup files as text files, did a search and replace to exchange the new URLs for old, being careful not to alter anything else.
Finally the updated backup files were imported to the new databases. Worked great. Simple process <grin> once I figured it out.
Good luck with yours.
