You can use id.getGuid(). This method returns a variable of type long. You can also use someJobFile.getGUID(). This method returns a variable of type String and is direct suitable to use as target.
It is possible to optimize your query a little bit. Look at this query:
//PipsAndSubbies.JobTaskMapping
[PipsAndSubbies.JobTaskMappingJob/PipsAndSubbies.Job/PipsAndSubbies.JobJobFile = %s]
When you use the constraint 'association = some_guid', it works the same like 'association/object/id = %s'.