Got it.  It's because VMWare Fusion either:

a) isn't able to request authentication to eject the disk

b) can't eject the disk because it's busy (can verify this - open Disk Utility and try to unmount the disk there.)

Fix:

Open Terminal (in your Applications folder, under Utilities), run the following command:

sudo umount -f /Volume/BOOTCAMP/

This will forcefully eject the bootcamp partition.  (Will ask for admin password.)

After that, try to open it again.

I'm not sure I have an answer to your problem, but I have a question. I am having the same problem and I wonder whether you are running 10.5.2. I had VMware Fusion running perfectly, but had other major problems and finally Genius Bar found a hardware problem and replaced my laptop. It came with 10.5.2. I used Boot Camp to partition and install Vista Business. I installed the additional Leopard drivers as instructed by Boot Camp that included a Boot  Camp control panel. I then installed VMware Fusion and it's update Version 1.1.1 (72241). The Boot Camp partition shows up, but I got the same error message you are talking about. I went to Vmware Fusion File>Open Recent and it shows Vista. I clicked on Vista and it told me it couldn't find it, but gave me 2 choices for an answer and noted if I didn't know which to choose, to select "I copied it" which I did. It then opened my Windows Vista. Now Windows Vista shows up as a choice in the list. When I select it, and hit "run" it will bring up the Windows Vista, but without the Boot Camp control panel. However, my internet works as does my usb printer. The Windows is unstable, however and crashes often with a different error message than I have seen before. I think the Windows was more stable in 10.5.1. I don't know if this will help you. I'm still interested in accessing my Boot Camp Partition in VMware as I did previously, if anyone knows how to do this safely.

I'm actually using Tiger 10.4.11 with the latest VMware also. This all started also after I replaced my hard drive with a bigger 320GB and loaded boot camp and installed Vista Ultimate on it. Then loaded VMware with no luck, just the same error. I went as far as loading Parrallels to see if that would work and no luck. I will try what you did by opening recent under VMware. I just have to wait until I get my Macbook Pro back from Apple. I just dropped it off today Saturday, my optical drive was malfunctioning, so they are changing it out under warranty. I should get it back Tuesday the 2nd. In the mean time I just have to wait and see if anyone else ppost something else. By the way anyone know what command under terminal will mount the Windows Untitled drive back. I type sudo mount /dev/disk0s3 /Volumes/Untitled and I get a resouses busy so it doesn't mount the drive. But this doesn't affect how VMware sees the drive though it still sees it.

Yes I can boot to Vista or Mac fine. If I choose Vista while booting up under bootcamp it works great. Its just when I try to run Vista with VMware that I get the error. Thanks for the suggestion.

Ah, here's a possible reason for "resource is busy" - I can get that error if I try to mount the drive when it's already mounted:

benjamin-juangs-macbook-pro:~ benjamin$ df

Filesystem                    512-blocks      Used Available Capacity  Mounted on

/dev/disk0s2                   222035968 207870744  13653224    94%    /

devfs                                212       212         0   100%    /dev

fdesc                                  2         2         0   100%    /dev

map -hosts                             0         0         0   100%    /net

map auto_home                          0         0         0   100%    /home

/dev/disk0s3                    11710944  11206240    504704    96%    /Volumes/BOOTCAMP

benjamin-juangs-macbook-pro:~ benjamin$ sudo mount /dev/disk0s3 /Volumes/BOOTCAMP/

/dev/disk0s3 on /Volumes/BOOTCAMP: Resource busy

Perhaps you didn't successfully unmount the drive?

As for remounting, open Disk Utility (in /Applications/Utilities/), then select your grayed out bootcamp volume (if it's not grayed out, you didn't successfully unmount it).  Then click "Mount" or go to "File" > "Mount "BOOTCAMP"", where "BOOTCAMP" will be whatever you named your bootcamp volume.

The command you listed "sudo mount /dev/disk0s3 /Volumes/BOOTCAMP/", may or may not work for you... after I unmounted and tried to use the mount command, I got the error "mount: realpath /Volumes/BOOTCAMP: No such file or directory".  I think you may need to do a mkdir /Volumes/BOOTCAMP first, so there's a place to mount to?  Not sure, never did this in MacOS X this way.

Yes this is very odd after installing the larger hard drive. I did increase the space for bootcamp. Before the larger hard drive I had reserved 30GB, and now with the larger hard drive that I installed I made 80GB for Vista Ultimate.

Also about mounting the Drive, it does show up on my Mac OS desktop but the eject icon doesn't show up next to the drive after I ran this comand from a earlier post I typed "sudo umount -f /Volumes/BOOTCAMP" I can see it fine but thought I might need it to show the eject icon if I every get VMware working. I would post a screen shot of what I mean but my Macbook Pro is at the Apple store getting the optical drive replaced and wont get it back until about the 2nd.