Importing from AD to SD version 5.

I have been having a problem importing to SD from AD. We have just over 2200 users in AD and the imports keep failing. I have tried importing from several of our 6 DC's with the same results each time. I have even tried limiting the number of users being imported to less than a 1000 by choosing sub-containers. No luck. I tried using a csv file (comma delimited) but that only created another problem as it added to the list of requesters unlike the import from AD which replaced the requesters. So now I have 3 Joe Smith's, with less information than needed, instead of just one. Our company has a 1 year trial with SD so I hope this fix is coming very soon. We are the beta shop for 4 other sites within Canada.