Your VI does not contain test data, so we have no way to check your actual signal.
The Timing and Transition Express VI works as expected as long as you have at least one transition, see attached (modified) VI.
The error message you get tells you that your signal didn't have an appropriate transition to analyze, so correct your acquisition to make sure this is not the case. Also a good way to debug your VI is to add a waveform graph tso you can actually visualize your signal.
