Martin from QlikView support recommended I point to the local drive.
When I changed the vbscript to point to a local drive letter e:\ rather than the UNC path of the SAN which we are using, the export worked!
I don't know why the UNC file path is not working. This is still an issue, as we have multiple development and production servers, with SAN attached directly to only one of these servers. So, I may want to run this process (and save the exported QVD to the SAN) on a different server than the server which has the SAN attached, thus requiring UNC.
Any thoughts on working around or through this? or Fixing this???