In all honesty it sounds like you have other problems that are causing the samba server not to become the master-browser. Or in other words, not being the master-browser is another symptom. Not the cause. Being the master-browser does NOT have anything to do with being able to connect to a network share or not. It is simply a left-over technology from days-gone-by from old "NETBIOS" days. The master-browser is simply a machine who is currently most-likely the guy who knows the most about the local network. The only information that server has/provides is a name-association to an IP address for a specific type of service. The list is not typically crucial, as other methods of discovery are tried. When in doubt, you could always create a lmhosts file and hard-code values on one machine in the network to ensure the values are correct.

In most networks today, all this lookup-stuff is done with DNS. (...and in corporate networks before DNS they used WINS) NETBIOS stuff is rather messy and excessively chatty on networks.