Files can’t be added directly from a network

Good Day To All,
I am at office working on my presentation using Windows Live Movie Maker, I meet an error when add a file directly from a network folder into Movie Maker, an error message appeared on my screen, I pasted below the screen shot of the error.
Windows Live Movie Maker
Files can’t be added directly from a network folder into
Movie Maker. Copy the files to your computer, and
Then try again.
As I looked on the error message above, I am wondering why I can't add a file directly from a network folder into Movie Maker, I've been doing this before, the suggestion in the error message is not appropriate to me,
Please share some other suggestions that might lead me in getting rid of this error message,
Thanks a lot.
