convert to seconds issue

[larry at significantplanet.org]

I am converting a future date to seconds with

convert theseSeconds to seconds

When I use this date:  
4/15/34 6:47 AM

I have no problem.

But as soon as I go to:

4/15/35 6:47 AM  (2035) or higher, LC won't convert it, but just leaves it as the date/time

I'm using 6.1.1 (rc 4) on XP Service Pack 3

TIA for any help

Larry