Server host won't let me upload .dll

I am trying to reinstall Mani Mod on my game server, but now, for some random reason, it won't let me upload .dll files into it.  There is already another .dll file there, but I can't delete that one. Any Ideas?

Do you have remote access to the box?
The other idea would first be to talk to your host.
Second, remove the extension and upload the file.  then re-add the .dll

Do you have remote access to the box?
The other idea would first be to talk to your host.
Second, remove the extension and upload the file.  then re-add the .dll

What do you mean by having remote access to the box, also, I tried to remove and then upload, but then when I try to put it back it on it says file extension is not allowed.