Slow file uploads

I am using Cold Fusion to upload files onto a Windows 2000 server.
What would cause the file upload to be very slow when uploading large size files?
For example it takes about 10 minutes to upload a 40 mb file using ColdFusion web page with the CFFile tag.

Is it a Intranet connection issue or Cold Fusion issue or Server issue?

sounds like a slow net connection to me, though 40mb upload in 1o minutes isn't that bad.