Error 0x800700DE when copying files over the network

Hello,

I am getting the "error 0x800700DE: the file type being saved or retreived has been blocked" when copying files with several special characters in them. all users are running windows 7. the folder size is 1.17 gig but this happens even when i copy individul files. When I rename to file to a simpler format ie: Deerwood test rather than Deerwood I&II_13..(just and example) and it works. I notieced it doesn't like the & (ampersand).

Is there a known flaw with windows 7 copying large file names and\or special characters to the network? any help would be appreciated.

thanks