I think you hit a very nasty bug inside Joomla.
Sometimes, if a component fails to create the menu entry, your menu table gets corrupted: Joomla will create the new entry outside the main tree (so you won't be able to select it) or, even worse, it will create it in the right place, put it is unpublished by default and the user has no way to enabled it (!!!).
Sadly these are Joomla bugs, they were reported long time ago, but they said that we have to wait for a proper fix...
Time is passing but no fix has been published, however we are working for a workaround that will be released in the next version.
In the meantime, I'd suggest you to try to reinstall TrackTime (without uninstalling it), if the menu is still missing, please try to uninstall and reinstall again.
I'm sorry for the trouble, but as you can understand, that's something not related to our software.