undefined function mobile_tools_menu_link_to_arg()

+1

Had the same bug. When I tried the dev version, that error didn't appear.
Upon doing a diff between 6.x-2.2 and 6.x-2.x-dev I saw this function inside 6.x-2.x-dev.

/**
 * Implementation of %mobile_tools_menu_link
 */
function mobile_tools_menu_link_to_arg($arg){
  return $_GET['q'];
}

There are a lot more differences between both versions of course but hey any clues help.

I fixed this by adding an empty function using that name to a custom module, like this:
function mobile_tools_menu_link_to_arg(){}
(you could put it in any module really)
Then cleared the cache, and removed the function again. The problem went away.