Thanks for the quick reply but the fields 'a' is already loaded in a table above to the code, i again need to rename that field and i need to join with other column which that columns is also pre loaded in a different table above to the code.
Remove all temporary tables using a cleanup script. There could be temporary tables created by Qlik in memory which are not getting dropped correctly. You can create a simple subroutine to find all tables and drop ,except for the main tables you want. Call the clean up subroutine towards the end of your script .
I encountered the "Error: Action canceled by user" today in a Qlikview reload. The reason for the error was: It aborted due to a full outer join generating close to 2 billion lines (where an interval match would have made more sense). So maybe "not enough RAM due to bad code written by developer" would be the correct translation of