The issues is or was that with Ubuntu 8.10 the kernel and NTFS have changed in a way that it became incompatible with VMWare workstation running virtual machines stored on a NTFS filesystem. ON Ubuntu versions prior to 8.10 this wan not an issue.

Once VMware started using memory-mapped files, it did not work with NTFS-3g, due to the lack of support for same. That was well-documented. NTFS has apparently changed to be "functional" but with poor performance. Either way, the solution is what it has always been since the inception of VMware's use of memory-mapped files: move your VMs to a fully functional file system that is intended for something other than read-write compatibility.