SQL & PL/SQL

I initially posted this question in the Oracle APEX forum, because that's where the problem is occurring.  But it feels to me that the issue is actually more PL/SQL-ish in nature, and not directly related to APEX at all, so I am reposting it here to get a different set of eyes on it.  Original post is here: https://community.oracle.com/thread/4076613

I have exported an application from Apex 4.2.  I am attempting to recreate it in Apex 5.  The export file is just under 100MB, and contains 1,255,229 rows.  The import process into the export repository on Apex 5 works fine.  When I then attempt to create a new application from that imported file, it runs for a while and then produces this:

"This page was already submitted and can not be re-submitted".

A google search discovers document 566839.1, which suggests that the application is timing out, and to try the import with SQL*Plus.  I tried that, but the process terminated itself and closed the SQL*Plus window very quickly, so that I could not see the error.

Therefore, I tried the import in SQL Developer.  The process ran through approximately 20% of the script, stopping in the section where it is processing page templates.  It processed the first several page templates, then stopped with this error:

......Page template 272698323505370117375

Error On Rollback

Error starting at line 196,798 in command:

<The 1,940 lines of PL/SQL that create the page template are displayed here in the error message>

Error report:

No more data to read from socket

The 1,940 lines of PL/SQL code for that page template don't appear to be different from any other page template.

At that point, even a simple select 1 from dual fails, with the same error message: No more data to read from socket.  So whatever the problem is, it is severe enough to sever the connection between my session and the database.

I suppose the good news is that it fails in exactly the same place every time, so at least there is a consistent situation we can diagnose.

Any thoughts?  Are there limitations in PL/SQL or perhaps SQL Developer that need to be considered, and/or extended?

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