error while using POOM

error convert from string "09/15/2006 12.00 am" to long is not valid

I need to add entry to the pocketpc appointment in wm5.It works fine when i directly give the date format in application

theAppointment.Start =newDateTime(2005, 05, 09, 09, 00, 00)

when i used combo.box to select date which is in format " 09/15/2006 12.00 am" it gives the error like this.

error convert from string "09/15/2006 12.00 am" to long is not valid

code using combobox is as:

[1158 byte] By [laja] at [2007-12-24]