I'm running OSX and I have both v2.3 and v2.4 on my hard drive, though in different folders. Just a couple days ago I started having problems with v2.4. When I would open up the chalkboard editor and double click on a player to either see his stats or substitute his position, I got the following message:
PMFB Error: -108 The application will quit.
This happens on every type of team file, from those created with the hidden roster spots to the ones that come with PMFB, and occurrs even when no PB is loaded. I have tried trashing v2.4 and re-downloading it and the problem persists. Running games works fine, as does the CE so long as I don't try to double click on a player. Strangely v2.3 has no problems.