Trouble with timestampts

Hi, i’m using WP 2.3 and on the server I currently am there is an issue with timestamp.

When I try to modify and set that into the future, everything is good. And, for example, i see that the post will be published in X minutes. But when this X tends to 1 minute, then it grows up again and the post is never posted.

I am sure this is a server issue, but i do not know how to fix it.