Not doubting you, but just one example.

My XP system was setup (either automatically or by a human) with

HOMEDRIVE=d:
HOMEPATH=\Documents and Settings\myusername
[download]

I should go add

HOME=%HOMEDRIVE%%HOMEPATH
[download]

though sweeping under the rug obvious problems with multiple users and delayed evaluation.

For the OP, it may help to dictate to his/her users that $ENV{HOME} be set correctly.