You are the victim of a stupid setup by the maker of your computer.
The recovery partition (currently D

on your machine is placed there by the
hardware maker to provide a way for you to 'recover' you machine to the
condition it was in when you purchased it. That includes destroying all of
your personal data and programs you have installed since your got the
machine.
When they set it up they should have hidden that partition, not given it a
drive name as they did.
You have two options, ignore the error, or remove the drive name from that
partition.
I recommend you remove the drive name, but it depends on how comfortable you
are with mucking around with your machine. The change is reversible and does
not affect the ability to 'recover' your machine if necessary.
Open 'Computer Management'
left click on the start orb in lower left, type
computer management
in the white box. At the top of the list that is generated should be
'Computer Management', click on it.
Give permission
Under 'Storage' click on 'Disk Management' will take a few seconds
in the display for Disk 0 you will see two or three segments, one will be
labeled D: and should be small (<10GB or so).
Right click on this segment and select 'change drive letter and paths'
You will be permitted to change or remove the drive letter assigned to this
segment. What you want to do is remove the the drive letter D:
This only changes the drive letter, now that there is no drive letter
associated with this partition Vista will no longer see the partition as
anything useful to it and will quit nattering at you. You can reverse this
change, it does not remove the partition!
Michael
Vista Home premium