You don't understand the startdates?
Take, for example, 19981211.1820
Let me stick some spaces in some helpful places:
1998 12 11 . 18 20
That better?
19981211 means 11th December 1998, and 1820 is in 24-hour clock format, IE 6:20PM
Stardates in the Star Trek universe work in an entirely different way. Wikipedia has a good explanation on how Stardates work.