When performing an action in the MS Word UI of DTM for iSeries, a job on the iSeries is created to execute the action.
When an error occurs performing the action, it can be helpfull to check the job log in the job on the iSeries side.
The job is created in QUSRWRK, called QZRCSRVS, but there can be several of these jobs.
So you will need to find the right one. The job log usually had a reference to the user that tried to log in, so in that way you can know whether you have the right one selected.
Once you found the correct job, you can check the job log for the cause of the error.