To use the Dell download manager you must have the Windows .net framework installed (use Windows update). Though it's not made clear by Dell, you DO NOT need the manager.
Go into your browser settings and delete all Dell cookies (or clear all your browser cache). Then go back to Drivers & Downloads and choose "download using my browser" when you select the file for download. You will then not need the Dell download manager at all.
Downloading drivers from Dell seems to work best with Internet Explorer (32 bit).
If you cannot locate the cache and cookies, the try using CCleaner to clear them.
If you still have problems with downloading the drivers, then please post back in the proper DELL Community Forum