PHP Version Switcher not function

hi, today have decided to downgrade the php version from 5.4.27 to 5.2.17 , but after click "start compiler in background " not update never , and if try to view the log  "tail -f /var/log/php-rebuild.log" compare this message

Code: [Select]

# tail -f /var/log/php-rebuild.log
tail: cannot open `/var/log/php-rebuild.log' for reading: No such file or directory
tail: no files remaining
 i have check but this file not exist.

after wait more time not downgrade the php version( remain the default version).

 I installed varnish a few hours before, but everything works fine


how solve ??

Was solved by support.
chmod 755 /var/run/screen