After researching the problem for a few weeks, I'm afraid there isn't a fix due to a bug in Windows Vista.
The Details - Short Explanation
The Windows OS function call available to get the location of the Documents folder returns a "NULL" when the Documents folder is set to the root of a drive. There is no other way Microsoft gives us to find the location of your documents folder under this condition.
Currently the only fix is the same as before: You can't have Documents at the root of a drive. Any application that refers to the Documents folder without using the Open/Save window will not work when documents are at the root of a drive.
The Details - Developer (Longer) version
In order to get the location of the Documents folder, the engine calls the function
SHGetFolderPath() with the target of CSIDL_PERSONAL. This function works from Windows XP and above, even though from Vista on up the preference is to use the newer
SHGetKnownFolderPath().
As first the speculation was something with SHGetFolderPath() wasn't catching the location change. When engineering did tests, they discovered both functions still returned "NULL" when the Documents folder was set to the root of a drive. When the location wasn't root, everything worked as expected. How it is that your Windows OS open/save dialog box works yet SHGetFolderPath()/SHGetKnownFolderPath() doesn't is beyond logic, but that's the situation. Maybe it's a security "feature", even with UAC turned off.
If anyone out there has a contact with Microsoft related to this issue, please put them in touch with me.