ORA-44410: XE edition single instance violation error

I am trying to run Oracle XE on Oracle Virtual Box

/oracle/db/xe/app/oracle/product/10.2.0/server/bin/sqlplus

"Error 6 initializing SQL*Plus
Message file sp1<lang>.msb not found
SP2-0750: You may need to set ORACLE_HOME to your Oracle software directory
"


cd
vi .bash_profile

export ORACLE_BASE=/oracle/db/xe/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/10.2.0/server/
export ORACLE_SID=XE

PATH=$PATH:$HOME/bin:$ORACLE_HOME/bin



source .bash_profile

sqlplus / as sysdba

"connected to an idle instance"

select * from dual
"ORA-01034: ORACLE not available"

startup

"ORA-44410: XE edition single instance violation error"

shutdown abort
"ORACLE instance shut down"

startup
"ORA-44410: XE edition single instance violation error"

GRRRRRR!


lsnrctl status

"Instance "PLSExtProc", status UNKNOWN"


The solution is provided by Paulo (thank you soooo much) in his comment:


I've run into the exactly same problem and made exactly the same mistake:

export ORACLE_HOME=$ORACLE_BASE/product/10.2.0/server/

Remove the trailing backslash from the path. Also add TNS_ADMIN. Here is my complete .bash_profile:

$ cat .bash_profile
export ORACLE_BASE=/usr/lib/oracle/xe/app/oracle
export ORACLE_HOME=$ORACLE_BASE/product/10.2.0/server
export ORACLE_SID=XE
export TNS_ADMIN=$ORACLE_HOME/network/admin
export PATH=$PATH:$ORACLE_HOME/bin