In Joomla 1.6 the component name specified in the manifest file has to follow the pattern 'com_componentname'. So here it should be
It will matter at least in the menu manager, where I discovered this problem.
In the section "Packaging an installation zip file", archive file offered as an example (located here: http://joomlacode.org/gf/download/frsrelease/11394/58225/com_helloworld-1.6-part01.zip) contains an XML file which has a line:
<extension type="component" version="1.6.0" method="upgrade">
<extension type="component" version="2.5.0" method="upgrade">
which should be fixed, I guess.