I'm having same problems.
I downloaded 3.0.2 version of CMS and 1.0 of the translatetable component and tried also the last code from git.
Configured default language and alternate languages. When into the backend I select the language and presso Go key, I obtain the same error:
"The action 'LangForm' does not exist in class CMSPagesController"
I've a big multilingual project, and this CMS is completely useless for me... :-(