Well, you can upload the package and use the installer to install the locally saved file but I doubt that this will solve your problem.
When a previous version of uddeIM is already installed you can also upgrade by overwriting the existing files with the new ones.
But your problem will still exist, e.g. when you install other components so you should first check your Joomla installation. As I said before in my opinion it is a permission problem, so chmod the mentioned folders.
uddeIM & uddePF Development
CB Language Workgroup
CB 3rd Party Developer
What I did was to "enable" ftp at the server configuration. Not disable according to your instruction. For some reason this works for me and I've successfully installed it.
Yeah, thats a big problem introduced with J1.5 which has already lead into discussions on Joomla.org.
I do recommend to disable ftp mode in Joomla 1.5 and to set the group ownership correctly. But there are some setups which require ftp mode.
Check if uddeIM is able to write its configuration file. Usually uddeIM is not able to access it since the permissions are not correct when installed using ftp mode (uddeIM accesses the file directly and not via ftp).
uddeIM & uddePF Development
CB Language Workgroup
CB 3rd Party Developer