Forgive me if this was posted, I did a search and didn't see it.

Is there any way to add Graemlins?

When I try, I get this message:
We could not move the Graemlin into the /images/graemlins/default directory. Please fix the permissions on this directory and try again.

then do it what you been told to do Your greamlin directory on your server dont have the propper permissions. Try chmod 666 or 777 to this directory and then try to upload your greamlins again.

You probable want to have 777 on the directory and 666 on all files so that you can delete graemlins as required.