A PHP Error was encountered

Severity: Warning
Message: Cannot modify header information - headers already sent by (output started at /var/www/clients/client2/web1/web/system/core/Output.php:538)
Filename: core/Common.php
Line Number: 573
Backtrace:

A PHP Error was encountered

Severity: Error
Message: xc_fcntl_create: open(/var/www/clients/client2/web1/tmp/.xcache.5004.8882.2.mutex, O_RDWR|O_CREAT, 0666) failed:
Filename: Unknown
Line Number: 0
Backtrace: