Problem with adding weapons to my server

[BertPls]

Im looking to add the m9k weapons to my DarkRp server as they are the most recommended ones that I see.
I downloaded Gmad and the easy extractor but every time I attempt to extract the file I get a strange error saying No File Name "File Within Addon Has No Name".
I have been following youtube tutorials and they don't seem to work when I follow their directions when I extract these mods. Also tried googling this error to no avail. Clearly I am either doing something wrong or I don't need to do it this way anymore...
Help is much appreciated thank you!