Getting SP2-0640 Not connected error on Sql Cmd Line

[bajajv]

Hi,
I have installed Oracle 11g Express Edition on my 64 bit Windows 7.
Later saw that this edition of oracle doesn't works on 64 bit Windows.
But I stilled tried on sql command line.
Getting following errors:
SP2-0042 Command not recognized (for sysdate command)
SP2-6040 Not connected (for create table command).
Is there any way I can run it on my machine.

Thanks.