What are you trying to do? Are you replacing fluxbox's native panel, or just want to add a pager?
If you just want a pager app, there is netwmpager:
http://crunchbanglinux.org/wiki/netwmpager_howtoIf you want a launcher there is wbar -
https://code.google.com/p/wbar/That is the default launcher in siduction, has animations like increased icon size and movement.
Adeskbar is another launcher -
http://adeskbar.tuxfamily.org/lxpanel is the only complete panel I know of that is probably still developed. The Xfce panel should have at least partial functionality in fluxbox, or you may still be able to use fluxbox as the window manager for xfce.
edit - The xfce panel appears to work just fine in fluxbox - I was thinking it lost a lot of funtionality. If you're just looking for a pager, you can create a panel that has the xfce pager as the only item.

edit 2 - the xfce logout dialog is what does not work, so you would need to exit from fluxbox.