Great!

SAMPLES>w !! do $system.OBJ.ExportUDL("Sample.Company.cls")


/// This sample persistent class represents a company.<br>
Class Sample.Company Extends (%Persistent, %Populate, %XML.Adaptor)
{

/// Define an index for <property>Name</property>.
Index NameIdx On Name [ Type = index ];

/// Define a unique index for <property>TaxID</property>.
Index TaxIDIdx On TaxID [ Type = index, Unique ];

/// The company's name.
Property Name As %String(MAXLEN = 80, POPSPEC = "Company()") [ Required ];

/// The company's mission statement.
Property Mission As %String(MAXLEN = 200, POPSPEC = "Mission()");

/// The unique Tax ID number for the company.
Property TaxID As %String [ Required ];

/// The last reported revenue for the company.
Property Revenue As %Integer;

/// The <class>Employee</class> objects associated with this <class>Company</class>.
Relationship Employees As Employee [ Cardinality = many, Inverse = Company ];

------<skip rest> -------

Thanks for the clarification.
It's sometimes hard to guess the picture if you miss some pixels.

I'd still recommend moving the CLOSE after each inner loop to have OPEN / CLOSE strictly paired

The implicit CLOSE happens only if you exit the partition. There's no class to act undercover. 
Curly braces just structure the code with no operational side effect.

It seems you have manually changed the class definition.

A normal RegisterdObject has no storage definition.
from <Type>%Library.CacheStorage</Type> i see it was a %Rersitent before.

Storage Default
{
<Data name="EOBListDefaultData">
<Subscript>"EOBList"</Subscript>
<Value name="1">
<Value>EOBList</Value>
</Value>
</Data>
<DefaultData>EOBListDefaultData</DefaultData>
<Type>%Library.CacheStorage</Type>
}

remove Storage and recompile.

I finally succeeded in reproducing your error

ERROR #5803: Failed to acquire exclusive lock on instance of '%Studio.ProjectItem'

The conditions are somewhat strange and you should take an exact check what applies in your case.
The story:

  • ENSEMBLE uses %Studio.Project to manage the export.
  • every item to be exported gets locked. The global  name to look for is ^oddPROJECT
  • if the number of items exceeds a threshold the whole Project storage will be locked
  • this is NOT possible if someone else has any other project in this namespace locked for him
    then the export will fail and you get the ERROR message. 

So try to find out in Terminal

  • USER>zn "%SYS"
    %SYS>write $system.SQL.GetLockThreshold()      ; most likely default => 1000

    xxxxxx
  • %SYS>d ^LOCKTAB
                       LOCK table entries at
                    16767728 bytes usable, 16774528 bytes available.
    Entry Process     X#   S#
    Flg   W# Item Locked
       1) 1016         1               ^["^^c:\intersystems\17e20\mgr\"]%SYS("CSP","Daemon")
       2) 6444         1               ^["^^c:\intersystems\17e20\mgr\"]ISC.LMFMON("License Monitor")
       3) 6752         1               ^["^^c:\intersystems\17e20\mgr\"]ISC.Monitor.System
       4) 12180        1               ^["^^c:\intersystems\17e20\mgr\"]TASKMGR
       5) 8568         1               ^["^^c:\intersystems\17e20\mgr\user\"]
    oddPROJECT("Ali")
     
    Command=>

Look if you see oddPROJECT

Next try to estimate the number of items your production will export.
If you get close to the dimension of  xxxxxx then you run most likely into your error.
Be aware that some components can create more than 1 entry. So your limit might be lower (70% ??)

You can increase the threshold in
MgmtPortal > System Admin > Configuration > SQL and Object Settings > General SQL Settings

ATTENTION:  If you set this value to high you risk an overrun of the LOCKTABLE.
        This blocks the whole instance.   Increasing the size of LOCKTABLE + Restart is then required. Or you set the limit t back.

I miss 3 things in this example:

  • There is a condition: I found no IF nor anything
  • at the end of the inner loop there is no CLOSE file1 7 /  CLOSE file2  for file1 or file2
  • OPEN file:("WNS": ......)   
    • W - Write is ok
    • S - Stream mode is OK
    • N - i s questionable. if you are not on VMS you override the file at each outer loop
      http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=GIOD_rmsseqfiles#GIOD_rmsseqfiles_use

      New file. If the specified file does not exist, the system creates the file. If the specified file already exists, the system creates a new one with the same name. The status of the old file depends on which operating system you are using. On UNIX® and Windows, Caché deletes the old file. (Note that file locking should be used to prevent two concurrent processes using this parameter from overwriting the same file.)

      So to get all output you may append arrayIndex to filename to have unique file names

as you noted SEEMS not to work.

method OnInit() as %Status

This user callback method is called via initConfig() from %OnNew() or in the case of SOAP Services from OnPreSOAP()

 $$$LOGINFO("INIT") translates to
   Do ##class(Ens.Util.Log).LogInfo($$$CurrentClass,$$$CurrentMethod,"INIT")

I'd suggest to replace it by set ^Antonio($i(^Antonio))=$lb($ZDT($h,3),"INIT")

so so find out if your Init gets called or not or multiple times, .. 
Especially during init phase high independence from the rest could be useful

My final idea:
- restart the whole ENSEMBLE instance to get rid of anything that might be hidden/hanging around in memory.
     It's not my preferred solution, but with the actual information, nothing else seems to work.
     If someone starts screaming you may have identified you opponent that blocks you. 
- if the problem persists further then contact WRC 

From your screenshot, I see that you have a running production.

#1) ENSEMBLE has an internal locking not seen in LOCKTABLE.
#2) If you try to export the actual running production this might be you might get in conflict with this internal protection.

I found no note that you can't export a running production.
Though I've never heard of such attempt as a production consists many dynamic moving parts.

Suggestion: STOP the production you want to export and then try the export again.