Milter-greylist

These errors popped up my maillog after a reboot this morning:

Jan 26 07:29:52 ciscy milter-greylist: unknown token "[" line 387, skipping 
Jan 26 07:29:52 ciscy milter-greylist: unknown token "]" line 387, skipping 
Jan 26 07:29:52 ciscy milter-greylist: unknown token "@" line 387, skipping 
Jan 26 07:29:52 ciscy milter-greylist: error at line 387: syntax error 
Jan 26 07:29:52 ciscy milter-greylist: unknown token "[" line 442, skipping 
Jan 26 07:29:52 ciscy milter-greylist: unknown token "]" line 442, skipping 
Jan 26 07:29:52 ciscy milter-greylist: unknown token "@" line 442, skipping 
Jan 26 07:29:52 ciscy milter-greylist: error at line 442: syntax error 

After poking around a bit, I deleted the greylist.db file and that seems to
have solved the problem.  If that was it, what might have caused it to be
corrupt or have an invalid value?
-- 
  Steve