Well, it kinda tells you right there, you have the file name wrong in whatever you are typing. You may want to add a bit more detail to your post, like what you are trying to do when this comes up, application name, what you tried already, etc...
Listen to your upstairs neighbour! Provide more details!
Anyway, I'm guessing you want to rename or delete a file/folder and you get that error.
Maybe your file names/folder names contain characters from the extended character set...
1.Try renaming/deleting (depends on what you want) the files/folders from safe mode (f8 key on startup)
2.You can try renaming/deleting the files/folders via command prompt.
(if you don't know how to use cmd I'll provide more details)