Are you talking about a conventional "data log" that is the periodic (and often-flushed) data source for Trend objects ?
Or are you talking about the target file for one of the ActiveX objects like DataStore or DataStorePlus ?
The ordinary PanelView Plus doesn't give you much to work with in this regard; it locks away the OS and the file system pretty well. The "PV+CE" allows FTP access to the file system, as do all the PV+6 terminals.
When I've needed to copy (or delete, or replace) files inside the PV+ file system, I've used an Autorun.exe executable along with a .BAT batch file to act on files in the file system. I'd have to go dig it up... there's an Autorun that works with the x86 terminals (the 700,1000,1250,1500) and one that works with the PV+ 400 an 600, which are based on a different chipset.
Do you know which \StorageCard\xxxx file path the file you want is in ?