I have bbPress as a subdirectory of my WordPress directory and run my own web server which hosts both. This post is FYI and also would like to hear suggestions on preventing similar occurrences in the future.
Here is what happened. Suddenly, when trying to get into either WordPress or bbPress from the internet, the pages came up blank. Thanks to my apache error log I saw the possible problems and finally wound up replacing two files from the original installation package to my working directories as follows
replaced "formatting.php" in ...\Forum\wp-includes directory
replaced "wp-functions.php" in ...\Forum\bbpress\bb-includes directory
The dates on the files in the working directories had been changed to today's date. After replacing the files with copies of the originals, all worked again. I marked both files as read only (don't know if that helps or not though). Everything still works.
Anyway, I wanted to post this here, one to help anyone else that might incur the same problem and also perhaps one of you gurus out there might tell me why this happened and how to prevent it in the future. I have my suspicions, but I would like a WordPress/bbPress "expert"