When users browse a web site on any Apache server they are automaticaly seen as user "nobody".
When a web page upload script is used any uploaded files end up being owned by "nobody". This is also true for Joomla.
If a template has been uploaded through Joomla template manager it will be owned by user "nobody" and the account user has no edit rights over the files.
In this case SSH / root access is required in order to change file ownership back to the account user.
This does not apply to FTP uploads as you are actually connecting to the server as yourself and any uploaded files will have correct permissions / ownership.
For security reasons we do not allow SSH access on our servers but we are always more than happy to assist with this.