Exchange 5.5 OWA problem

When using Outlook Web Access (exchange 5.5 sp4 on Windows 2000 svr SP4), the links that open specific email messages in the inbox point to invalid locations. For example, when viewing my inbox in OWA, I click on one of the message links to open a specific message, the screen says ?page cannot be found?. The problem is that the link for each email is not correct. It points to exchange/IPM.NotefrmRoot.asp instead of exchange/IPM/Note/frmRoot.asp. The IPM.NotefrmRoot.asp is created by a variable called %classpath%. I have searched through the OWA web page files to try to determine where this variable is defined but no luck. For some reason, the classpath variable is not formatting the path correctly and I don?t know where it is getting its info. Any ideas how to fix this???