roles and privileges 101

Ok, can some point out the reason for the following:

resource is granted to a role. role is granted to user. user schedules job (dbms_scheduler) to insert some data into a file. job errors with: ORA-01536: space quota exceeded for tablespace

resource granted directly to a user and problem goes away.

i know that execute on procedures/packages can't be done through roles but i roles to roles to users shouldn't be a problem correct?

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