I don't quite get the first error you are talking about ,, however the second error could be easily over come. it appearers the master browser selection is dynamic in your network,, you need to force one computer in your network to be master browser,, you need to make a small registry changes, follow the link here:
http://www.winguides.com/registry/display.php/54/
furthermore,, you life will get easier with your network if your master browser would proforma the DHCP as well,, there are lots of article on the net in regards to Master Browser Election in the network.
cheers