This is just a guess but since you haven't actually 'created' a Tk object with 'new' , Perl may be complaining that there's no object with which to associate Tk::Event.
Of course, if I'm wrong, we'll hear about it soon from the monks more experienced with OO and with the Tk modules.
I'm afraid that your guess is wrong. As I said in my earlier response, "Can't locate loadable object..." means that a dynamic library file associated with the module couldn't be found. This error is unrelated to a module being object-oriented.
In this case, the loadable object could not be found because the auto/ directory, in which it was installed, did not have the expected permissions. More often, the error occurs because a module has been "installed" by a user who just copies the .pm files into an @INC directory, instead of using `make; make test; make install`.