I am not a big fan of delimiters however here is the solution:
DCount("EmployeeName", "tblAttendance", "[AttendanceDate] = #" & Format(txtAttendanceDate.Value, "mm/dd/yyyy") & "# And [EmployeeName] = '" & cboEmployeeName.Value & "'")
pbaldy was right about the double quotes; however I had to...