Can you post the contents of your "DSLauncher.log" here, through a pastebin link?
You should be able to find it in the same directory as the launcher executable.
Something you can try, is opening up 'launcherconfig.xml' and removing any entries under the <PatchHistory> tag. (They should look like '<Patch>somehashvaluehere</Patch>')
That'll force it to redownload things.