Oracle Database Discussions

hi all,
here i hav a question to you,actaually i try to drop the tablespace 'test' before dropping i tried to take the tablespace offline. i gave
sql>alter tablespace test offline;
but it returns
error:ORA-00959 tablespace test does not exist

now i queried "select * from v$tablespace" to check is that tablespace exist or not. there it shows the tablespace exists.
actually there are no users alloted to this tablespace.so i try to create seperate user and try to allot this tablespace for that user but i cud't, again it shows same error.
i dont know watz the wrong i did? can any one help me to solve this issue.

Thanks and Regards
Boo