Hello analog, It looks like you are passing out of your vi the reference to the unnamed worksheet rather than taking the worksheet reference out of the right side of the property node. It=92s possible than correcting this will solve your problem.
If none of these suggestions help, or if I=92m not correctly understanding your issue, please post a wrapper for this vi which exhibits your described behavior, and I=92ll be happy to look further into it. Have a nice day! Robert M Applications Engineer National Instruments