Well after doing some research it maybe your ISP as I have found many forums suggesting that Netzero can block you from certain sites and control how you use the internet...
You could try these fixes, but unfortunatley that's all I can suggest...
Try changing limwires listening port..
Go to Tools > Options > Advanced > Firewall and enter the number 64049 into the listen port box and select apply...
You could also try this...
Try uninstalling all versions of Java from the add/remove programs and then re-install the JRE 5.11 offline version....
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11
If that does not help with your problem try deleting your preference folder/s...
Fixes for Limewire when LW isn't operating as it should