Sounds like an ownership problem. If you are using an apache server and everything is owned by nobody:nobody you won't be able to do anything until it is changed.
This has been a big problem for many people for a long time, a post here on joomla forums with some more info -
forum.joomla.org/index.php/topic,9987.msg82253.html
If you have joomlaxplorer you can use that to see who owns the directories.
You need someone with root access to chown [ change ownership ] the directories to your own usergroup.
Post edited by: MikeHell, at: 2007/05/22 23:43