seahawknationblog - Let's do one problem at a time.
I JUST rolled a multisite to a single install with no issues. So I know it can be done.
1) Right click on the image and make note of where it's pointing (http://domain.com/files/2011/03/09/foo.jpg for example)
2) Go into Options -> Media and check where THAT is storing uploads. Normally it's
Now. If they are DIFFERENT you want to CORRECT them :)
Either change the location to
files (using my earlier URL example) or search/replace the database to change http://domain.com/files/ to http://domain.com/wp-content/uploads
And then you STILL want to toss in a .htaccess rule to redirect
/wp-content/uploads for anything you miss.
FYI, normally you actually edit the export file to fix the URLs before importing.
Also all our articles 3000 of them have no category attached to them or an author, somehow this information was lost in the xml export?
That sounds like this problem: http://wordpress.org/support/topic/lost-categories-in-import-of-wordpresscom?replies=16
If you're really having this much trouble, and it's costing you guys money, go to http://jobs.wordpress.net and post, or look for a consultant to get you sorted.