"If you are using an older version of Windows XP (without Service Pack 2) or Windows 2000, you may need the BITS 2.5 update (Background Intelligent Transfer Service 2.5) before using Dial-a-fix checkmark #3."
The update linked to here is for "Background Intelligent Transfer Service (BITS) 2.5 for Windows XP" and lists only Windows XP Service Pack 2 as the "Supported Operating Systems". So will BITS 2.5 still run on W2K (but unsupported by Microsoft)? Sorry if this sounds a bit like a noob question, but it's one that I'd hate to find out the hard way if the answer is no. On the other hand, if the answer is yes, the article could make this clearer.