It is definitely a good thing. What this means is that if HTC and Verizon come out with an over-the-air delivered update to the stock ROM, since you are running a custom ROM you do *not* want the patch to install on your phone. It probably would not install successfully anyway, but...

For a custom ROM, you would generally need to download the full ROM zip file and install it manually. If you are having issues with your phone, yes, there may be a way to fix it. It may help if you say exactly which custom ROM that you have. You may find a name in settings->about phone. It may be under "software information". There should be a name in something that resembles English, rather than a bunch of numbers, somewhere.