can not resize datafile

Hi,on 11g R2 11;2.0.3 on Win 2008,
I try to reduce the size of a datafile but I receive :

ORA-03297: file contains used data beyond requested RESIZE value

This file belongs to a tablespace in which there are tables with the name as  :

BIN$CqVRNpt/SXeRZ9X/FlieZw==$0

What are these tables ? I can't shrink them :

alter table sysadm.BIN$CqVRNpt/SXeRZ9X/FlieZw==$0 shrink space

01735. 00000 -  "invalid ALTER TABLE option"

Then can't move them ?

Any idea ?

Thanks.