At what point does the brick wall appear? Is it as soon as you open LW & it doesn't disappear? I am aware not all belkin's are reliable with UPnP. But if it's worked fine for you in the past, there's no reason it shouldn't still work fine.

Are you using the resume/find sources function on all your incomplete files? If yes, & if you have a lot of incomplete files this can overcome the device. The mere traffic forced upon it overwhelmes it. Thus it's better to apply it to only 2-3 or so files at a time.

If you haven't used LW in a while & this has started happening, then close LW & delete your LW prefs folder (but make a note of important settings! Because next time you open it you will need to reset all your options.) Your LW prefs are found here /Users/your_username/Library/Preferences/LimeWire

BTW are you using your OSX firewall? Check to see if it's active. If yes, make sure LW is ticked as an option for clearway. But intermittent brick wall sounds more like unreliable UPnP. Keep in mind after opening LW that sometimes the brick wall can take anywhere from a few seconds to several mins for some people before it disappears.