Cross-LPAR Queries in SQLRPGLE Throws -519 Error Intermittently

I have written a program that retrieves record-level data from files on one
LPAR (as the source) and inserts rows to the local files LPAR (as the
target). I have been getting SQL0519 errors that appear, speculatively on
my part, to be caused when the SQE on the source LPAR appears to not close
its cursor for a previously issued Select statement.

It happens intermittently. For example, I may have to retrieve data for
100 files (at a record-select level by specific field values) and the
program will process 40 SQL's but then throw a -519 for the next 60. When
the program gets the -519 all subsequent SQL-Selects throw the same error.
When I log off and restart the program it will show me the 60 that were
not completed (after calling the program and refreshing my subfile list)
but then throw a -519 after processing 20 SQLs. This is all being done
through a interactive program so that the user can accept, or exclude, file
gets from a list. The format of the SQLs is all the same.

exec sql insert into *local_library.local_file*
select * from* source_dbname.source_library.source_file *where
*source_field = value*

then EXECUTE IMMEDIATE.

Here are some real examples (same local library, same remote system &
library):

Insert into ARENTITY.CUPPC select * from PRISMSYS.ARENTITY.CUPPC where
trim(PCCO) = trim('9830')

Insert into ARENTITY.CUPCRGRP select * from PRISMSYS.ARENTITY.CUPCRGRP
where trim(CGCO) = trim('9830')

Insert into ARENTITY.CUPVL select * from PRISMSYS.ARENTITY.CUPVL where
trim(VLVER) = trim('983')

The interactive job log shows this message:

Prepared statement _ in use. *(where the statement is blank)*
This statement is the SELECT statement for cursor _ that is currently
open. *(where
the cursor name is blank)*

I have done lots of research over the last two days and my colleagues are
at a loss also. Please, please, help if you can.

Gratefully,

Robert Wenzel
Developer
Inmar, Inc.