First thing - if you have those asterisks in the file they will cause a problem.

Second - you don't export the ORACLE_SID=avoora2.

Third - it worked fine when I added it to my /etc/profile ( I only tested the following lines:
#########################
MAIL=/usr/mail/${LOGNAME:?}
ORACLE_HOME=/scratch/oracle/8.1.7
export ORACLE_HOME

ORACLE_SID=avoora2

JAVA_HOME=/usr/j2se
export JAVA_HOME

LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:${ORACLE_HOME}/lib
export LD_LIBRARY_PATH

TNS_NAMES=${ORACLE_HOME}/network/admin
export TNS_NAMES


What is the shell and userid that you are testing?