
Your (part) menu code from IndividualEffectiveness.asp looks like this:
<li class="parent link"><span class="link"><a class="link" href="../LearningSolutions.asp">Learning Solutions</a></span>
<ul class="level-1">
<li class="parent link"><span class="link"><a class="link" href="../LearningSolutions/Expertise.asp">Areas of Expertise</a></span>
<ul class="level-2">
<li class="link"><span class="link"><a class="link" href="../LearningSolutions/Expertise/IndividualEffectiveness.asp">Individual Effectiveness</a></span></li>
<li class="link"><span class="link"><a class="link" href="../LearningSolutions/Expertise/TeamEffectiveness.asp">Team Effectiveness</a></span></li>
<li class="link"><span class="link"><a class="link" href="../LearningSolutions/Expertise/OrganisationalEffectiveness.asp">Organisational Effectiveness</a></span></li>
<li class="link"><span class="link"><a class="link" href="../LearningSolutions/Expertise/SalesEffectiveness.asp">Sales Effectiveness</a></span></li>
<li class="link"><span class="link"><a class="link" href="../LearningSolutions/Expertise/LeadershipEffectiveness.asp">Leadership Effectiveness</a></span></li>
</ul>
In the level 2 menu links, the '../LearningSolutions/' part of the link is telling the browser to go back one directory and then look for a(nother) 'LearningSolutions' directory inside the 'LearningSolutions' directory.
So for instance, that last link takes you to:
LeadershipEffectiveness.asp
not:
LeadershipEffectiveness.asp

You have described the problem perfectly. This is what I am trying to fix. Of course I'm still looking for the solution. The problem occurs only when you are on one of the second level directory pages and are trying to use the menu.
The whole site uses the same SSI file:
upnav.htm
Why does the menu fail to function only when displaying pages which are 2 folder levels up as linked from the menu?