KOSOVAR1  Jon Nathan from the developer replied to my email within minutes with an easy fix to the problem I was having, (described in a previous message). FWM still has a few rough edges, but it is still very useful. Customer Support deserves five stars though.

Here's the fix: (Thanks, Jon!)

The best solution is to quit FWM (if it is open -- you may need to use

Activity Monitor in your /Applications/Utilities folder to send a quit

command to FWM if it is not responding) and then move the preferences file

to the Desktop. This will most likely cure the issue. The preference file

can be found in your preferences folder (~ is shorthand for your Home

folder):

~/Library/Preferences/com.jen.fwm.plist

By moving this file, you will lose your Window Sets but it should correct

issue you are seeing. If it does, there was a problem with the original

preferences file and it should probably not be used. However, if you had a

lot of custom settings that would take a long time to reconfigure, you can

send the original preference file ("com.jen.fwm.plist") you moved to the

Desktop as an attachment to a reply to this message and I will see if I can

eliminate the corrupted data and preserve your existing settings.  
(Version 1.9.7)

KOSOVAR1  It's too bad to have to give one star to a program that used to be very useful. But after buying the most recent iMac model (2009, 2.93 Mhz) running OSX 10.5.7, FWM stopped working altogether. It tries to start up, then crashes with Error message "FWM AFN Error (PrefWindow) Can't make 0 into type boolean."

Can anyone advise?  
(Version 1.9.7)

VASILIS  This app rocks! Making sets of finder windows is just what I need. I move and copy things all the time.

The basics are very simple but there are some very nerdy looking preferences. This only means that it does way more than I want. and I think that's OK. Once I figure out what else it does I might be even happier.

There is one thin that is missing: you can hide all apps when you restore a set, but what's needed is that you bring the sets to the front.  
(Version 1.9.6)

DANA SUTTON  This app. really needs some detailed documentation.  
(Version 1.9.6)