ora-01033.oracle initialized or shutdown in progress

[KULJEET]

i face problem in oracle backup.
i take oracle logical backup after 3-4 days.
but now the database is run 24*7 days

so i set the oracle on archive mode

at last night i take the hot backup by

alter tablespace user begin backup;
hot ocopy E:\ORACLE\ORADATA\SAFEDB\USERS01.DBF d:\ora_data;
alter tablespace user end backup;

similar on other tablespaces

after it i take control file backup
alter database backup controlfile to trace;

and alse on archive log file
host ocopy c:\oracle\ora81\arc01223.001 d:\ora_data

every thing if fine.
due to some reason i shutdown the system(database)

at next morning when i start the database
it gives error
ora-01033.oracle initialized or shutdown in progress
after connect / as sysdba

shutdown immediate
startup
now it gives message
ora-01113 file 3 need media recovery
ora-01110 datafile 'user01'

what's the reason of problem.

bye