Have you complied with all of the requirements and restrictions for shrinking?
See this forum post - it mentions many of them.
Post the info ask for in that post for your table and tablespace settings.
See the DBA Guide
You use the Segment Advisor to identify segments that would benefit from online segment shrink. Only segments in locally managed tablespaces with automatic segment space management (ASSM) are eligible. Other restrictions on segment type exist. For more information, see "Shrinking Database Segments Online".
The syntax is correct. Please check if the tablespace is with segment space management manual.
The subpartition is with compression=ENABLED. So, accorfing to the that link you provide me, this explains the error message...
SQL> select COMPRESSION from dba_tab_subpartitions where SUBPARTITION_NAME = 'DWH_DCE_RLP_2007_Q2_379';
Thanks for that tip!
You should ALWAYS check the documentation first when you have a problem using Oracle's functionality.