Trouble with "Write waveforms to file"

Hi folks,

I'm having trouble with "Write waveforms to file." Attached is a very simple vi that gives the error message: "Error 4 occured at open file ... LabVIEW: end of file encountered ... NI-488: invalid argument or arguments to function call." 

It gives this message whether I put in a new file name or one that already exists. 

The last part is rather puzzling since I'm not doing anything with GPIB.

I found this KnowledgeBase article, but this is not the same case, since it happens the first time I address the file:

http://digital.ni.com/public.nsf/websearch/0576444C8FD4DC0F86256E83007FA540?OpenDocument

This is Windows 7, LV 2013 SP1.

Any advice would be much appreciated!