I just did my first SBS 2008 install and after the server went into production, the OWA was not working. I read that a fix may be to simply re-install the CAS Role.
I stopped the exchange services and then went into maintenance mode, unchecked the CA Role to uninstall it. After going back in to re-install the CAS Role, I could not, because it was looking for the Exchange installation files to be located in C:\Program Files\Windows Small Business Server\Bin\CMPNENTS\EXCHSRVR80. Turns out the CMPNENTS folder is there, but does NOT contain the EXCHSRVR80 folder!
I then discovered that there is an EXCHSRVR12 folder on the 2nd SBS DVD, but this generated an error when trying to use the install files located on the second DVD to re-install the CAS Role.
Does anyone out there running SBS2008 have the EXCHSRVR80 folder? Is there something I'm missing here?