I've got the same problem as the one mentioned in the author's site's comments:
Alx / 11-12:
June 4th, 2009 at 1:10 pm

I was using J1.0.15 and ever since I upgraded to J1.5.11 I cannot see the tooltips with the "views" counts any more. I read the authors reply and searched for the term "Archive Module Count Parameter and Tool Tip corrections" in Google and found some solution for the Archive module, but it doesn't do anything to this module... How to implement these changes to the Most Read Recent / Popular of Late in order to see these tooltips again? I am using a J1.0.x template remade for J1.5. Please be more specific as we are not that professional PHP developers... :) Anhialo.info

Otherwise regards for a wonderful module! :)