Thanks Lieve.
Well, even in the video that Lefthook77 published on YouTube, he is using 5.5, and he has: cpInfoCurrentFrame. Did you double check to make sure you really don't have: cpInfoCurrentFrame, maybe you missed it.
Are you sure you downloaded the 5/5.5 versoin of the Michael's widget?
Unfortunately, I don't have 5.5 on my computer so I'm at a loss as to what else to offer.
If you really don't have cpInforCurrentFrame. I'd probably try uninstalling and reinstalling the program, but before you go that far, maybe someone else has a suggestion.