Sounds like you are comparing text strings instead of real dates. What about if you add a GetAsDate ( ) around all you date expressions ?
Edit : After seeing you shots, you are comparing numbers and "/" is a division but the answer remain the same...
Thanks, that fixed things! It's worth mentioning you have to put the date in quotes or it will not work.
GetAsDate(8/15/2015) does not work.
I am glad to hear it is solved.
And yes, the parameter of GetAsDate(Text) have to be a text string which have to be between "".