Using same dabase files in two different computers

I carry both database files (*.rmd and *rmx) in a pen and open them in my desktop RM as well as my laptop RM (wherever I happen to be working)… 

However, when I add records in my laptop (a Vaio with office 2007 and Vista) and then copy the 2 files into the pen and open them with my desktop RM (also with office 2007 and vista), I do not see the new records added in the laptop RM.

What is going on here?

Thanks.