Assuming that your control_file_record_keep_time parameter is defaulting to 7 days, this suggests that you are archiving a log file every 9 seconds, consistently! If that's right, you would do well to use much bigger log files.

PS: Prior to 8.0.6 this error can make LGWR crash. If so, you may need to create a new control file before you can get the database open again.

Has anyone seen is this message displayed in their alert log?

Mon Feb 12 11:31:39 2001
kccrsz: denied expansion of controlfile section 9 by 2026 record(s)
  the number of records is already at maximum value (65535)
krcpwnc: following controlfile record written over:
 RECID #462191 Recno 12154 Record timestamp
 02/05/01 16:05:11
 Thread=1 Seq#=462191 Link-Recid=462190
  Low
scn: 0x0000.04ae4dca
 02/05/01 16:05:09
 Next
scn: 0x0000.04ae4df7