Can't open activity db: Permission denied error for SVN commits

On my way to work this morning I got an emergency call from developer who unsuccessfully tried to commit latest java code changes to Subversion repository using TortoiseSVN. The developers was getting "Can't open activity db: Permission denied" error in TortoiseSVN client when he tried to commit or create a new tag in SVN.

The Apache error log had this lines related to SVN commit problem
Could not create activity /!svn/act/9dac40a3-4acf-3456-b328-a2598c258d06
Could not open dbm files
Can't open activity db: Permission denied

Just in case I have run svnadmin verify on Subversion repository, but as expected there was no problem at all. Then I noticed that the files on the dav folder of the SVN repository are not writable by Apache server. I changed files permission and successfully committed files with TortoiseSVN again.

The configuration used in this solution

• SVN 1.4.6
• Apache 2.0.49
• Tortoise 1.4.7

Unfortunately no references related to SVN commit problem were found in Subversion FAQ or TortoiseSVN FAQ

Update: I set permissions for "activites.pag" and "activities.dir" files in dav folder to 777