Hi Lars, just wanted to update on this issue. here is how the index error fixed. the table was partitioned to 16 nodes and one of the blade went down on a fail over scenario. after redistribution the index was corrupted either cant rebuild it nor delete it. this was showing the error i posted initially. Once the blade was up and when we re distribute the tables,i was able to drop the index with out error.
Also on the execution plan error, we were able to put 240 threads in parallel for select and with help of product support team we identified it as an error in the executor.ini time out configuration. we were able to get rid of the error with some different time out settings in executor.ini.
-Thanks
VInod Nair