Aha! That's the very issue! And I'd say you trying to cure a consequence instead of a cause. One of developer rules I discovered is to NEVER ever rely on any regional settings other than for displaying purposes. Especially where any kind of communication between two PCs involved. In your case, DB should never accept or send a timestamp as a string. Just never. If there's no such ability, just carve timestamp format in stone and use it everywhere for internal communication. Of course, for display purposes use local settings (f.ex., American mm/dd/yy format makes other people crazy).
@Sherlock it wasn't clear enough