I run Norton 2004 firewall on all PC's, house the media on it's on HD on the server an do most of my media activities from my laptop across a linksys 2.4ghz network (in AP mode, not AH). My 11yr old daughter accesses media as well as my room mate. As you can imagine, privacy was the biggest issue I had to address in order for sharing my media library no mater how I did it. But if you don't care about the privacy issue try this.
Make sure that if your firewall has the ability to scan your computer for programs that access the internet as part of it's configuration options, that you have done this (on every PC you will be using to with Media Server). Then, again as part of the configurations, make sure your firewall is set up to all the connection through that port and that the pc's you are "serving" are in the trusted sites list of the firewall. Lastly, and I don't know why this worked, disable the firwall on the server, start media server, connect from what ever PC's you plan on using with the "find media servers..." and then reenable the firewall on the server when the pc's have connected. This mostly worked for me, hokey as the last part seems.
If you have a situation where security is an issue or where you would like to more easily allow access to those parts of your library to only the people you want, read on.
An alternative to using media server for sharing and accessing your library from other PC's, especially if you want some parts of the library accessable to some users in the house/on the network, but all of your library accessable to you and from any pc you are using is what I am doing.
I have the luxary of several large HD's on my server allowing me to compartamentalize my library files. I run XP pro on my server as it gives me a great deal more security options at the file and folder level via permissions and because I have used XP home alot and they are virtually identical. I put the music, home movies, images and such that are okay for anyone in my house to access on one drive, and have it shared. Any other material that I don't want accessed by anyone but me I keep on another drive and have used several security mechanisms to ensure this to the best of my ability. Then I share it! If you need help with securing the folders or network and such there are those far more qualified then I, but if you ask me, I'll tell you what I know. Moving on!
Next, on every pc you will want to access these files from, do the following:
Map! the drive(s) your media is housed on (this is because you may later want to turn off the folder option to automatically find network shares and or you may want to set your server to not broadcast one of the shares).
Install MC on them.
Import files into MC by selecting to scan only the appropriate drives for the appropriate users PC. Now you are done (unless I forgot something).
The obvious drawback is that you must redo the library at every pc, but the other users have to do this anyway, so to them it's a wash. I have a work around for you if you want that involves using MC to move the files to folders you create and name after the genre or rating or both or whatever. This process is a bit cumbersome, but it has the added advantage of overcoming, to some extent anyway, the ID3 tag issues of what your library(s) in MC show vs. what is actually saved to the file. This way, when I reimport to MC or import to any other player, setting up the library is much faster and easier. God forbid you have to reinstall, but if you do, you need only reimport your files folder by folder making the batch changes in MC library of the folder name in the appropriate MC field one by one as you go.
I know there must be a better way to do this, but I found no help in the forum when I investigated this originally for MC10 and have not seen anything mentioned since then to indicate that MC10 or MC11 can accomplish what I need. I don't know if there are other significant drawbacks to my tip, perhaps someone with greater experience and knowledge can help us both.
BTW, software that hides files and folders, encrypts sensitive data inside them, locks them and so on didn't help with this much either. I tried this as one of the many solutions I researched in an attempt to make use of the media server feature.
Good luck