try to set the firewalls to accept limewire on the macs. can you do anything else related to the internet with the macs browse a site for example. otherwise (not being a mac person it's hard to be right) but I think there should be a version for macs of limewire on the site and also try getting the latest java, and look at the options, or preferences under tools. look for anything that could be changed but remember what you changed so you can go back on it