Mmm that is strange, what if you do the next:
1. Unregister the VM.
2. Download the .vmx and add the following line:
3. Create a directory for Swap files under the datastore.
4. Add the next line into the .vmx: sched.swap.dir = /vmfs/volumes/datastore_name/dir_name
5. Upload the VMX, register and Power-On the VM.
However this is to confirm that it works is not a definitive solution as this is per VM config.