This problem is very similar to the one described in http://communities.vmware.com/message/1524727
The solution described by Scottee seems to involve writing grub into the MBR which - if I did understand this correctly - would conflict with using rEFIt. Here's a short summary of the problem again:
triple boot with Linux on a non-bootcamp partition #3, Windows (not yet) on a bootcamp partition #4
boot manager is rEFIt, grub is installed on the Linux partition
when started from rEFIt -> grub, Linux starts fine
I created a rawdisk for this partition using vmware-rawdiskCreator and configured the VM to boot from it
when starting the VM, grub enters the rescue shell saying "error: no such partition"
Scottee described a solution involving several invocations of grub-install. As I understand the trick is to start into the VM from an install CD so that one can issue a grub-install command to repair the setup:
5) Boot VMware Ubuntu from Install CD, grub-install --force (hd0), grub-install --force (hd0,3) , reboot the VM and ensure it now works.
Now I'm not quite sure about the consequences. As it looks to me this would mean installing grub in both the MBR and the Linux partition. This seems to make sense as in the original post grub was used as the main boot manager. Is there a way to get a working setup for both triple boot and the VM without having to install grub in the MBR?
Also, out of interest, what exactly causes the problem and how is the above supposed to fix this (I mean, if grub's understanding of the partition table is different if run from rEFIt or from the VM, can there be one setting which fixes both)?
Grateful for any hint 