Let me see if I can type this out in a way which makes sense...

Ever since upgrading from Slack 11 to 12, X & Fluxbox have formed a strange relationship.

If the system's default runlevel is set to 4, users are not able to launch any apps which are configured in Fluxbox's menu with the [exec] keyword. All internal/built-in Fluxbox commands perform as expected; it's only those which are spawned from within a shell which fail.

However...
Set the system's runlevel to 3, log in as a user, and issue the startx command. Up comes the X session, and any command contained within Fluxbox's menu may be launched.

...

There are two significant differences between each scenario. Firstly, X is launched via xdm instead of xinit.

Secondly, for each scenario there is a difference in the location of an "authfile". In the first scenario, the authfile is created in /usr/lib/X11/xdm/authdir/authfiles .In the second, the authfile is created in the user's home directory.

I'm relatively innocent when it comes to X. If anyone can give me a push down the correct path I'd appreciate it!

My guess is that the two different methods of starting x create different configurations for the shell. You might even be running two different shells. You can check by issuing the following commands both in level 3 and level 4:

echo $SHELL

echo $PATH

printenv

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Steve Stites

Right on the money, jailbait. Thanks.

$SHELL is null for users when up under runlevel 4.