"Directory world-writable" warning

[Edmund]

In the log file, there's a warning message everytime bind 8.1.2 startup,

Directory . world-writable

I studied the code and realize that the message is generated as a
warning of directory "." is writable by the others, however, no idea on
what "." directory is ?    Anyone knows ?   Is it a security warning of
a security hole in the system ?  Please help.  Thanks.