I encountered the same some days ago even when the SYMGEN is ON !!! I restowed several times my programs but result unchanged. However, it suddenly worked after lunch. I don’t know why.
It was when trying to debug under SPoD my programs residing in remote UNIX machine.
It’s just a wild guess: Maybe this problem has to deal with the Bufferpool. Just try to turn it off by setting BPSFI to OFF in your Natural Parameter Module.