Is it just the 4 lines that seem incorrect? Does the rest of the SQL*Loader logfile contents look correct?
That seems very odd - for some reason you are seeing the clear text of the SQL*Loader message file for those 4 messages.
It could be that your binary message file is corrupt for some reason.
If you go to $ORACLE_HOME/rdbms/mesg is there a ulus.msg file?
If so, can you backup the ulus.msb (note the extension is msb, not msg).
Then try running:
% lmsgen ulus.msg rdbms ul american