its a general php problem. php 4 doesnt handle timestamps before 1970. have a google around for this.
if you want to hack the php you may be able to have negative timestamps and write some code to interpret this. if you look on the php.net/strtotime comments you'll find people with similar issues and workaround.
i believe php5 handles the negative timestamps more gracefully than php4...
I think that's a problem in general: that's hard to find extensions in the contrib and everyone re do the same things (see the countries ones), then ez develop something similar on its own.
I'd help if the contrib could be made more visible in the documentation...