A news version of the simple newsletter component for Joomla! and Mambo is available: Letterman 1.2.3. This is a maintenance release which fixes compatibility issues with Joomla! >= 1.0.9 and Mambo. I have also added a spoof check for the subscriber module so your subscriber table won't get spammed.
If you want to update an existing installation of Letterman, please do not uninstall it before. Just upload the newer files from the component archive file (com_letterman_1.2.3.tar.gz) into the directories of Letterman - (/administrator)/components/com_letterman and overwrite the existing files. If you can't access those old files from ftp, just use joomlaXplorer.
Letterman 1.2.3 (102kb; 2006-07-02)
Letterman Subscriber Module 1.2.3 (2.7kb; 2006-07-02)
Letterman Search Mambot 1.2.3 (1.8kb; 2006-07-02)
Changelog:
- fixed compatibility issues with Mambo 4.5.3 and Joomla >= 1.0.9
- added "Spoof Check" functions like in Joomla 1.0.10, to prevent subscriber spam
- new search mambot allows searching through all newsletters