You should replace "exec wmblueclock" with "wmblueclock &", and make sure it's placed before the fluxbox line.
"exec" tells bash to replace the current process (xinitrc) with wmblueclock, and the result is that the rest of the script is not run. If you have "exec fluxbox" before wmblueclock, Fluxbox will run and wmblueclock will never run. If you have just "fluxbox" before "wmblueclock", then Fluxbox will run and wmblueclock will try to run when you shut down fluxbox.
If you add "&" after a command, bash will run that command in the background and continue to the next line in xinitrc, so if you have
wmblueclock will be run in the background allowing the script to continue on, and so fluxbox can then be launched.