physical Standby database -- 10.1.0.3.0

The ALTER DATABASE OPEN READ ONLY; command hangs and its not giving the 'database altered' message and its not returning the prompt, when i open the another sqlplus
window and check the open mode its read only...is there anyknow issues..This command is part of my recovery script and therefore its not performing the rest of the job in the script...any issues with this command in 10g standby ...