I am getting an error: "The host from which you are accessing the board is not recognized as a valid host. This is more than likely related to a firewall issue that is blocking the referer variable. Check your firewall settings and try again."

This was after I changed some settings on FireFox as follows:
What setting to I need to return to the default in order to get UBB to work again?

How to prevent your browser form sending information to web sites
After following the steps below, you’ll be much harder to track. Coupled with our VPN service to mask your IP address and private email service, your Internet footprint will be as minimal as possible.

1) Cookies and history are the oldest of the tracking methods. Modern websites will not work well without them but they need to be managed.
Make sure cookies and history are deleted every time you close your browser.

Under Tools/Options/Privacy:
Do not check the ‘private browsing mode’ box (this is false security).
The following boxes need to be checked in order to properly clear your cookies/history:
Accept cookies from sites
Accept third party cookies (drop down box should say ‘Until I close Firefox’)
Clear history when Firefox closes
Click on the Settings tab in the Privacy window.
Check all of the boxes so that it clears everything when you close the browser.

Newer versions of Firefox include a box to ‘Delete Flash Cookies’. This is important and if you have an older version, upgrade to a newer one that includes this essential option. Or, you could use the plug-in named Better Privacy to clear the flash cookies. However, it is no longer necessary with the newer version of Firefox and adds an identifying marker to your browser that is unnecessary.

Following the steps above will allow browsing on sites to proceed without issues but will clear everything every time you close the browser, which you should always do when going from one web site to another.

2) Now add the plug-in No Script

This will prevent server-side scripts from running in your browser without your permission. This plug-in blocks all java scripts from running on web pages. This is both a privacy and security plug-in. By preventing the applications from running the instant you visit a page, there is little risk of malware affecting you in the background if you go to a compromised site.

Modern web sites have hidden links to a multitude of other web sites. Many of these scripts that load have nothing to do with the function of the site you are visiting. They are scripts that connect you to other sites like FaceBook, Google, Double Click, Twitter, etc. This allows these outside sites to track your activity across the Internet even though you never went to their site. By only allowing the essential java scripts that make the desired web site function, while preventing the others, you increase your privacy significantly.

After installing this plug-in most sites will not operate properly. You have to train the browser for each site you visit as to what to allow and not allow. No Script will give you a nice drop down menu telling you what sites are attempting to run scripts and then you can pick the ones that apply to the site you are on while rejecting the trackers.

By default No Script allows well known sites to operate freely. We suggest you change the default setting to restrict everything and then set all permissions manually. For example, If you go to a website that uses Google Analytics to track their visitors then Google will try to load google-analytics.com and run the java script to track you. If you have this disabled in No Script then you are less trackable without any functionality loss. All the search engines, tracking sites and social networking sites operate the same way. All of them are out to get every last bit of information on you in order to make money.

3) Prefetching

Firefox has a feature called Prefetching that downloads pages (in the background) that it thinks you are going to click on in the future. This is a serious security flaw since in order to make this guess it’s saving lots of information of your previously visited sites.
To turn this off, type:
about:config
into the address bar of Firefox and press enter.
Agree to the warning about making changes to the system.
Type:
network.prefetch-next
into the search bar
Right click on the option and select Toggle to change the setting to False.

4) Referer logging is used to allow websites and web servers to identify what sites you previously visited.
To turn this off, type:
about:config
into the address bar of Firefox and press enter.
Agree to the warning about making changes to the system.
Type:
Network.http.sendRefererHeader
into the search bar and set the entry to 0.

5) With Geo-location Firefox will try and tell websites where you’re located

To turn this off, type:
about:config
into the address bar of Firefox and press enter.
Agree to the warning about making changes to the system.
Type
geo.enabled
into the search bar
Right click on the option and select Toggle to change the setting to False.

6) Mozilla has a feature called ‘DOM storage’ in recent versions of Firefox which can be used to track you.
To turn this off, type:
about:config
into the address bar of Firefox and press enter.
Agree to the warning about making changes to the system.
Type
dom.storage.enabled
into the search bar
Right click on the option and select Toggle to change the setting to False.