Welcome, mrcelery.
I have no idea what might be causing this, but I'll suggest a few things that might help. It sounds like you've tried it already, but just to be sure... locate your database somewhere on your C: drive (which I'm assuming is where PVD is installed). Put it someplace other than the default "My Documents" location—the program's attempt to locate that might be the cause of the problem. Start the program and attempt to Open the file at its new location. If you can't open it...
Restart the program using the portable.bat file in the installation directory. This runs the program with the -portable switch which causes the program to use a configuration file in the installation directory. Since there isn't one, a new default configuration file will be created. That should eliminate your configuration file as the source of the problem. If you still can't open it...
Please report exactly what happens.
Thanks for helping.
The database has been tried in a few locations, as you say. On your advice I moved it again from the 'C:\Program Files(x86)\Personal Video Database' folder to 'C:\Users\Steve\My Videos', and started the program. I immediately got the "4:Unable to complete network request to host"QNAPMedia" Failed to establish a connection. The system cannot find the file specified" error message, followed by a further two messages: "Failed to open database", then "file is not a valid database. Connection authorisation failure. Error Code: 3".
Trying 'File > Open...' at that location gave me a list of all movies in the left column, but nothing in the centre for about two minutes, just a blank white screen. Then everything (data\images) finally appeared. I assume that is because it is re-indexing – I have a list of 1,000+ movies.
However, when I reboot my PC, I’m back where I was – getting the same error messages: 'Documents data folder could not be found!'
I then ran the portable.bat file in the installation directory, which gives me the Command line box with 'C:\Program Files (x86)\Personal Video Database>”viddb.exe” -portable', and opens the program but nothing populates the left menu or centre. Any attempt to open the database using 'File > Open...' gives the error message: 'An error occurred in the application' with a number of button options.
I did copy the database to a laptop running Vista, and it worked fine there. Which makes me think it is a NAS or Windows 7 issue.