how to change $ORACLE_HOME

>
> I have tried this once and it worked OK. Now when I do this I get the
> following errors when executing the script to produce the new control
> files.
>

  Tried this once may be the problem. When you try the script once, the control file will be created and the database will be mounted and opened. So you may not be able to mount the database again. Write back if this is not the scenario.
> ORACLE instance started.
> ORA-01503: CREATE CONTROLFILE failed
> ORA-01565: error in identifying file
> '/database/system/PROD/system.dbf'
> ORA-09782: sfifi: another instance has the same database mounted.
> ORA-01507: database not mounted

Good Luck

---
Mani Maran                                           EDS Consultant
Voice: 214-828-7572.... Fax: 841-6886                999 Haskel
Commercial Services Division, Southland Account  Dallas, Texas 75... USA
"Opinions expressed herein are not necessarily supported by my employer."