hi,
i encounted the same problem and i solved it this way:
use text editor to open the .vmdk file, for example Windows Server 2003 Standard Edition.vmdk
remove the disks added recently, for example,:
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s001.vmdk"
RW 2099200 SPARSE "Windows Server 2003 Standard Edition-s002.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s003.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s004.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s005.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s006.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s007.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s008.vmdk"
RW 12288 SPARSE "Windows Server 2003 Standard Edition-s009.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s010.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s011.vmdk"
RW 2101248 SPARSE "Windows Server 2003 Standard Edition-s012.vmdk"
remove
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s010.vmdk"
RW 4192256 SPARSE "Windows Server 2003 Standard Edition-s011.vmdk"
RW 2101248 SPARSE "Windows Server 2003 Standard Edition-s012.vmdk"
and start you vm again

hope it helps