One question that comes to mind is if this device has ever been used with NI-DAQmx Base (perhaps it was used on a Mac or Linux previously?). If so, the driver probably needs to be switched back to NI-DAQmx as detailed in this knowledgebase.
The first computer sounds like it may have a corrupt driver installation. You can fix this by uninstalling NI-DAQmx 7.5 and reinstalling it. If you installed it from a CD, I recommend downloading it from our website.