For what you are doing, there shouldn't be a good reason for multiple bind files. Here are my common WS binds that I use, so you should just be able to modify them for being a PB.
C "powexectoggleoff black dwarf$$powexectoggleoff dark nova$$powexecname eclipse$$gototray 1$$bind shift+lbutton powexecname shadow step"
E "powexectoggleon Black Dwarf$$gototray 9$$bind shift+lbutton powexecname black dwarf step"
ALT+E "powexectoggleoff black dwarf$$powexectoggleoff dark nova$$powexecname sunless mire$$gototray 1$$bind shift+lbutton powexecname shadow step"
G "powexectoggleoff black dwarf$$powexectoggleoff dark nova$$powexecname Nebulous Form$$gototray 1$$bind shift+lbutton powexecname shadow step"
Q "powexectoggleon Dark Nova$$gototray 8"
ALT+Q "powexectoggleoff Dark Nova$$powexectoggleoff Black Dwarf$$gototray 1$$bind shift+lbutton powexecname shadow step"
T "powexectoggleoff walk$$powexectoggleon sprint$$powexectoggleon athletic run$$powexectoggleon combat jumping$$powexectoggleon shadow cloak"
SHIFT+T "powexectoggleoff sprint$$powexectoggleoff athletic run$$powexectoggleoff shadow cloak$$powexectoggleoff combat jumping"
V "powexectoggleoff black dwarf$$powexectoggleoff dark nova$$powexecname stygian circle$$gototray 1$$bind shift+lbutton powexecname shadow step"
TAB "targetenemynext$$targetcustomnext enemy sapper$$targetcustomnext enemy alive quantum$$targetcustomnext enemy alive void$$targetcustomnext enemy alive cyst"
SHIFT+TAB "target_enemy_prev"
SHIFT+LBUTTON "powexecname shadow step"
C is for WS to drop forms and use eclipse
E is to switch to dwarf form and switching the tray to dwarf powers
Alt+E drops me back to normal human
G is similar to the C bind, but for a different power
T is for turning on travel powers and Shift+T is for turning them off
V is my healing in human form
Tab is for targeting quantum and sappers
As you can see, I switch trays depending on what form I am using, without multiple bind files. I suspect your new error is from the secondary bind files. You should be able to use this as as template and just add or change to PB powers.