I Do Not Understand Why This Happens Please Help Me Squid -z

squid -z

2012/08/06 06:41:17| Local cache digest enabled; rebuild/rewrite every 3600/3600 sec
2012/08/06 06:41:17| logfileOpen: opening log /dev/null
2012/08/06 06:41:17| /cache/00: (2) No such file or directory
FATAL: Failed to verify one of the swap directories, Check cache.log
for details. Run 'squid -z' to create swap directories
if needed, or if running Squid for the first time.
Squid Cache (Version 2.7.STABLE9): Terminated abnormally.
CPU Usage: 0.012 seconds = 0.008 user 0.004 sys
Maximum Resident Size: 14816 KB
Page faults with physical i/o: 0

I do not understand why this happens please help me