Oracle Message ORA-08104 - this index object string is being online built or rebuilt

ERROR	this index object string is being online built or rebuilt
CAUSE	the index is being created or rebuild or waited for recovering from the online (re)build
ACTION	wait the online index build or recovery to complete

869521	Oracle <= 10g: TM locks with REBUILD ONLINE / CREATE ONLINE
682926	Composite SAP note: Problems with "create/rebuild index"