Well, as you've already found it looks like meta files are broken in your version of tk2d. Did you copy use version control without adding meta files / share via dropbox? That means that the demos won't work properly if you scene does and vice versa. I suggest keeping your project as is (broken) - your stuff will work fine, you'll have difficulty merging new versions of tk2d.
There is no way to fix this apart from manually reassigning the missing scripts to the demos.