This is a defect or limitation in fuse4x. Its complaint, "mmap being attempted with no region accessibility", is entirely bogus, since it is specifically permitted to mmap a region with no accessibility. The documentation for mmap(2) even reveals that there is a defined constant, PROT_NONE, that the caller of mmap should use to request that the region be mapped with no accessibility. That's what we are doing when this failure occurs in fuse4x.
I would expect that this failure will occur whenever an attempt is made to power on a VM whose .vmem (the file which backs the virtual machine's RAM) is located on a filesystem provided via a version of fuse4x with this problem.
You may be able to work around the problem by using virtual machine config options to move the .vmem file to another volume which does not need fuse4x. (I don't immediately recall which options... others here might, or I can try to dig them up...)
To really fix this issue, you'll have to find a filesystem driver without this limitation, whether it's a newer version of fuse4x or another filesystem driver altogether.
Cheers,
--
Darius