Failed to evaluate FilterExpression when using CDate

I have been getting the above error when attempting to add date pickers (startDate and endDate) to a simple report.  

So, I have been troubleshooting and narrowed down the issue to something having to do with CDate.

I found that this filter on the DataSet works:

[Date_Name]

=

="Wednesday, January 23 2013"

But I get the error when I use this filter:

CDate([Date_Name])

=

=CDate("Wednesday, January 23 2013")

Apparently I do not understand CDate too well, but I (regrettably) only use SSRS a few days out of the year, so this is a little bit confusing to me.