Materialized View Hangs with no error

Can anyone help me on this?  I am trying to create a materialized view but every time I try, it just hangs.  I never get any error but the MV is never created.  It is a complex view with unions.  I can use this same code to create a view and create a table with success but not a materialized view.  What am I missing? 

nbsp;                             curr_apft,
            SUM (med_non_deploy) med_non_deploy, SUM (candidates) candidates,
            SUM (officers_no_ba) officers_no_ba,
            SUM (officer_pipe) officer_pipe,
            SUM (security_clearance) security_clearance,
            SUM (gains_last_month) gains_last_month,