task is done does not work for multiple finite digital output task calls

I need to create a program that cycles two digital lines a variable number of times for a finite duration each time. 

Several years ago, I modified the Multi-Function-Synch AI AO.vi and called it to perform a single finite digital output task.  I have modified the program to call the digital lines six times each individually and eight times together based on the number of cycles completed.

This new program works on a desktop computer (Dell Precision 390 with an Intel Pentium 4 at 3 GHz, 1 GB ram, and a PCI-6251 using LabVIEW 7.1 and NI-DAQmx 8.0.1f0).  The program does not work on the laptop that will be used during the actual testing (Dell Latitude D820 with an Intel Centrino Duo T5500@1.66 GHz, 1 GB ram, and a USB-6251 using LabVIEW 7.1 and NI-DAQmx 8.3.0f0).

On the laptop, the task is done stops the Multi-Function-Synch AI DO for Vibe.vi on the first call but not on the remaining calls. 

Because this testing is being done on production test computers, I can not upgrade the version NI-DAQmx. 

I was able to get my program to work by switching to a finite analog input task.

Any ideas to explain why the “task is done” does not work for the finite digital task but the “task is done” does work for the finite analog on the USB-6251?  I may need to perform similar testing in the future on short notice and do not want to bang my head on the wall again when using the laptop and the USB-6251 when out of the office.