Roger,

All I can think is the synonym is wrong. Even though it as said synonym created, this doesn't mean the synonym is valid, you could put

create public synonym rubbish for nonexistant_script;

and it would say synonym created !

You may need to specify the schema of the owner of the script, so it would be.

create public synonym cre_backup_dbtest1_script for <procedure schema>.cre_backup_dbtest1_script;

Hope this is of help.

Mike