When a CIL compile doesn't complete properly subsequent CIL's may fail with the following error: "Another instance of CIL generation is already in progress. Please wait for the operation to complete before retrying.".
To rectify this issue by delete the following record from the SYSLASTVALUE table
select * from SYSLASTVALUE where ELEMENTNAME = 'CIL Generation'
delete from SYSLASTVALUE where ELEMENTNAME = 'CIL Generation'