samba - May 2007 - Samba shares OK- but only after 'getent passwd' ?

Hi there,

I have just configured Samba on a new server and Im having a bit of 
trouble with it - after it boots, it dosn't want to share until I've 
issued the 'getent passwd' command...? Otherwise, it appears to be 
running fine; 'wbinfo -g' and -u  are showing the correct info (that is,
the same as 'getent...' )

Anyone have any idea why this could be?

Thanks,
Kris