Sudden server access problem on one folder.

I got a call from a user this morning who said they can't get into their web based database editing tool. (phpMyEdit) Turns out that they were logging into the account successfully but the server would not allow the execution of the php script in a particular folder on an Apache virtual domain. It had been working for her all day yesterday.

So I change the chmod on that one folder to a 757 and now it's running OK.

All the other folders are working ok (apparently) for that domain.

I am the only root user on this system and I have not changed anything on that domain in weeks. I can't see anything unusual in the access logs.

Question is what changed from one day to the next and by what/who?