Unknown content in alert log

I was trying to run an "explain plan" for a problem SQL statement.

I got this message in the alert.log:

Mon Mar 05 11:12:45 2012
ALTER SYSTEM: Flushing buffer cache
ALTER SYSTEM: Flushing buffer cache
Mon Mar 05 13:25:29 2012
Memory Notification: Library Cache Object loaded into SGA
Heap size 100523K exceeds notification threshold (51200K)
Details in trace file c:\oracle\product\10.2.0\admin\customer\bdump\customer_s000_2772.trc
KGL object name :EXPLAIN PLAN FOR
-- put your statement here
  SELECT distinct
         case when 'N' = 'Y' then
            sa.currency_code
         else
             a.currency_code
         end as currency_code,
         a.customer_vendor_id,
         a.location_id,
         a.invoice_id,