Checkpoint not complete error

I've the environment of Oracle 10g (10.2.0.3) on SUSE Linux 9 (32-bit).

I've got 5 redo logfiles of 250MB each, still I'm seeing this the following error messages in the alert log file:

*Thread 1 cannot allocate new log, sequence 17640 Checkpoint not complete*

Users are also complaining of the slow database. What else can I do to make it perform better and get rid of the above message?

Thanks for the help.

Saad

--
http://www.freelists.org/webpage/oracle-l