[@_ck_ Participant 17 years, 2 months ago]

This was my fault apparently.

Somehow the pluggable.php within bbpress was built 1074 when it absolutely needs 1075 to have the new wp_salt function.

So future note for integration to others:

to use the new WordPress 2.4/2.5 trunk

you MUST use bbpress build 1075

build 1074 and build 1076 will not integrate properly as is