ODK Failure While Exporting to CSV

Hi All,

Yesterday I suddenly started having problems exporting survey data from an
ODK Aggregate server deployed on Google AppEngine into CSV format. We're in
the middle of a pretty big survey so I'm really desperate for some help. I
followed the instructions in an earlier thread where another user kept
getting the 'Error - Abandoned All Retry Attempts' message when attempting
to export. After getting a failure message I checked the error logs, did a
GQL query in the dataviewer, deleted the corrupted instance, and then
retried the export to find more errors. I did this for several hours, but
have kept getting errors messages and am still unable to export. We've
gotten around 1400 surveys (about 200 per day) so far, and this is the
first problem. I am worried there is a larger issue with the survey, and
our 20+ survey teams can't really have anymore downtime; they're still
giving surveys now, but are not submitting them to the server until the
problem is solved. Here are the exact errors I'm getting over and over with
different uuid #s, with the survey name redacted with '-----':

E 17:20:32.543 org.opendatakit.aggregate.query.submission.QueryByUIFilterGroup getResultSubmissions: Unable to reconstruct submission for opendatakit.---------------_CORE uri uuid:6f215d81-638c-438f-9b49-b22474f654de

E 17:20:32.573 org.opendatakit.aggregate.task.CsvWorkerImplfailureRecovery: Exception caught: org.opendatakit.common.datamodel.ODKEnumeratedElementException: SELECT * -----------------------_D20 WHERE _TOP_LEVEL_AURI = uuid:6f215d81-638c-438f-9b49-b22474f654de AND _PARENT_AURI = uuid:6f215d81-638c-438f-9b49-b22474f654de multiple-choice valueSet is missing an entry OR has an extra copy of one for ---------------

Please let me know if anyone can help!

Best,

Nicholas Makinster