Carl T
The problem you are experiencing is related to the differences in browser response to certain types of incomplete or short-cut web-page coding.
You are probably using Firefox browser that may not accept certain types of short-cut coding or codes that Microsoft offers that aren't STRICTLY "standard" codes.
When the previous month web-address is selected you'll notice that the address code does not show the full and complete address.
As an example:
The source code for the top item in last month's forum only shows:
EXAMPLE 1.) "HREF=../../Messages/616/M0087616.htm"
however the full correct address should be:
Example 2.) "HREF=../../Forums/Messages/616/M0087616.htm"
You'll notice that the folder "forums" is not included in the 1st example.
Firefox does not know what to due with a partial address so you get a 404 error.
The only reason that MIE does get you to the right location despite the missing code is because Microsoft's browser MIE, has not cleared out the last address buffer and therefore it defaults to the last known address left there.
Firefox more properly follows "absolute" strict coding and therefore if you do not give the full and proper address it spits out the error.
Here is the proper, more complete, address it should be pointing to:
http://www.nostalgiaair.org/forums/Messages/616/M0087616.htm
If you try using the MIE browser ( Microsoft internet explorer) you will not experience the problem.
That is because MIE will typically recognize their own non-standard coding.
Try it.
Open MIE as your browser ...and then go to NA and try looking at any previous month and it will work.