The Watchtower Library 2008 works with CrossOver version 7.1.
I installed it on an intel MacBook and an intel iMac both running OS/X 10.5.
I just did a standard install with CrossOver, creating a WinXP bottle during the install. I did not need to do any pre or post fixes, all works fine (except a few of the known issues such as not being able to view maps, etc)